Right I will try again with a simple mathematic example. If say we give Germany a rating of 100 and, using figures largely at random admittedly, OTL EU a value of 400 and TTL EU a value of 250. In the OTL example Germany has 25% of the total EU. In the TTL example it has 40%. That's what's I mean by the relative greater size of Germany in TTL compared to a smaller EU. We can argue about how much smaller but you will agree that it will be somewhat smaller.
I agree that past a point (not in the initial phase of its existence) it shall quite possibly be smaller because Britain and Scandinavia won't join it because their higher Euroskeptic attitudes shall conflict with its federalizing character and their ability to stand on their own shall allow them to neglect the material benefits of EU membership, and later the Southeastern European nations won't join it as well (unless possibly well into the 21st century) because of their own problems (socio-economic backwardness, ethnic troubles, corruption) and hence inability to fulfil EU membership criteria.
*sigh* You make it sound like membership in a democratic federal union such as the USA or TTL EU is necessarily going to mean predatory colonial domination and oppression for the involved area like it happened for the WP nations, but this is not really how the system works. No doubt the most obsolete portions of the E European economies are going to suffer or wither for a while from being exposed to competition in a larger, more advanced market, but the benefits of federal welfare are going to compensate for the hardship, and over time there is going to be greater overall development and prosperity from adapting to greater opportunities in a wider market, greater investments from the rest of the unions, development of secondary industries and services, and so on. In the medium and long term, the socio-economic balance is all but surely going to be positive for the area. This is more or less what it happened to E Germany after reunification and the same pattern on a larger scale is going to replicate about assimilation of Central Europe in TTL EU. If OTL is anything to go by, the E European peoples are going to care much more about these material benefits than about national sovreignty concerns, because in their rebellion to Communism they were rather more interested in getting the affluence, consumerism, personal freedom, and political freedom benefits of the Western model than getting absolute national sovreignty or keeping full protectionist control over their own industries. They were hostile and rebelled to Soviet domination mostly because it trapped them in a system than made them poor and oppressed.
Admittedly, because Russia had been such a terrible master, the peoples of the region have been quite anxious about preventing a possible comeback of Russian imperialism, and hence extremely supportive of anything that could contain it, most definitely and demonstrably including increased committment to their protection from their stronger Western partners, such as increased deployment of NATO forces in their territory, increased NATO integration, EU military and weapon industry integration programs. From their PoV, the more the better in this regard. Hence ITTL they shall be extremely positive towards the military aspects of integration in a federal EU and its Pan-European military for the stronger security benefits it provides, including 100% committment of W Europe to their defence, deployment of the bulk of EU military power at their own eastern borders, modernization of their own forces and military industries, and so on. Simple NATO membership would give them some of the above but not exactly the same, hence they shall go for the complete option. The nationalist concerns you voice won't likely almost enter their picture, also because they shall know unlike the WP they shall get a meaningful voice and vote at the table where the economic and military politicies of the Eu get shaped. If they pool their votes, the Visegrad Group states can approximate the influence of any of the other EU bigwigs, such as Germany, France, Italy, and Spain, within the European government.
As it concerns the military budget of TTL EU, no doubt it shall be substantially higher than OTL to make up for the lack of American contribution, but not overwhelmingly so since IOTL there is a lot of inefficiency and waste in army keeping two dozen separate NATO armies, even at the current good level of alliance integration. Fusion in a common army would allow to trim all this fat, and free up resources to strengthen the system in other ways.
I agree the Soviet empire is still going to have a somewhat greater military strength, at least on paper and in terms of brute quantity, than TTL EU. In practice, however, I expect the EU and its Anglo-Nordic allies are going to compensate more than adequately through reliance on better quality, superior doctrines, and more advanced technology, just like Israel did vs. the Arab states and OTL NATO did in the phases when it was not reliant on its nuclear deterrent. As it concerns standardization of equipment and doctrines, I may point out that OTL NATO was able to achieve a remarkably high degree of it for its member state armies in fairly quick and efficient way w/o any of the strife and difficulty you mention, and there is no good reason to expect it would be any different for the Pan-European military or its allies, if not for the fact federal integration of the EU core is naturally going lead to 100% standardization of its common army. As usual, your ideological extreme dislike of centralisation drives you to expect and predict a lot of nationalist strife even where historical evidence shows there wouldn't be any. As it concerns lingustic plurality, IOTL it has not been any significant barrier to OTL NATO working as a cohesive unit, but for obvious reasons I do expect over time multilingualism is going to become a de facto, if not de jure, prerequisite to get a career in the EU officer corps or civil service, and to be a successful EU politician, at least at the European, national, and regional levels. People interested in that kind of job with sufficient talent and ambition shall adapt, as they always do.
As it concerns Communist propaganda, they already tried a lot IOTL to paint W Germany as Nazism in drag and the West as a cesspool of poverty, strife, racism, and class oppression, by exaggerating such sore spots as incomplete denazification in W Germany or racism in the US South, to get their E European subjects content with their lot, and guess what, they failed miserably, because the E Europeans could easily use their own eyes compare their own poverty and oppression with evidence filtering to them through various channels that W Germany, W Europe, and the West as a whole were free and prosperous, and notwithstanding their flaws a much nicer and better place than the WP. Cranking up the propaganda volume even higher shall avail the Communists nothing.
Well, if we take OTL French interventions in Africa as an analogy for TTL EU ones, they have been fairly quick and successful touch-and-go operations, with little or no involvement in extensive or prolonged guerrilla conflicts that would create a serious burden for the EU. I struggle to think of Cold War situations where this scenario would be any likely, except perhaps for the Portuguese colonial wars, which took place before Portugal democratized and joined the EU, so by analogy TTL Eu military involvement does not seem likely. Even if somehow it would happen, Portugal had basically won the conflict in the military field, it ultimately pulled out because the authoritarian regime that fought for the status quo was on its last legs and the way out, and the strain was a tad too high for small and poor Portugal. Direct EU involvement seems unlikely, but even if it would happen, the much greater resources and firepower it would bring on the table would in all likelihood force an outcome more favorable to the Western camp, with defeat of the pro-Soviet guerrillas, Angola and Mozambique staying aligned to the West, keeping some kind of close bond with Europe, and allowing the European settlers to stay in favorable conditions, would be more likely than Europe getting a Vietnam-style defeat. Decolonization was inevitable after WWII but not the fall of Southern Africa in the Soviet bloc. ITTL it may well be the likes of UNITA and Savimbi instead of the pro-Soviet forces that end up running the show if the EU or for that matter the USA is somehow involved, and this may help a lot indirectly to ensure Southern Rhodesia ends up ruled by pro-Western moderates and the Mugabe tragedy is avoided, and transition to majority rule in South Africa is eased.
Back then in the 50s, the Western public opinion was not yet so squeamish that the relatively small losses of the Algerian War would necessarily generate widespread opposition to the conflict, especially if after a while the main justification for the conflict becomes to ensure a fair deal for the European settlers and pro-French Algerians, which IOTL got ethnic cleansing. Even IOTL, the French had achieved military stalemate at worst, so the greater resources EU involvement would bring on the table would likely allow a more favorable outcome to the conflict. By that, I am indeed thinking of a few relatively large coastal exclaves becoming a haven for the European settlers and pro-French Algerians, be it as a French/European overseas territory or perhaps better as an autonomous entity aligned with EU/NATO, a kind of pieds-noire Israel if you wish. I doubt it would be much more of a running sore than Israel turned out to be, especially if the EU minimizes direct military involvement in the long term, turns out defence of the territory to the militarized locals, and just gives them weapons like the West did for Israel. As for the Muslim reaction, sure the radicals are going to hate us and seek our blood, but so what? They could not possibly do it much more than they already did IOTL because of Israel and the rise of Islamism blaming the West for all the problems of the Muslim world.
Fact is, what I described is pretty much the attitude W Germany, W Europe, and the West as a whole already used IOTL to justify and support W German rearmament when it took place under national leadership within the NATO framework since the mid 50s. It took place with the full support of Western policymakers and Western public opinion basically went along with it, buying the 'clean Wehrmacht' myth which became the absolutely dominant view of the issue throughout the Cold War. The Western policymakers decided contribution of the resources the Germans could bring to the table to defeat the Communist threat was much more important than achieving absolute, merciless justice for Nazi crimes, and after they tried for a while they gave up, not only for the sake of Western solidarity but because they wisely realized past a point that kind of absolute retribution for the crimes of a past regime is unfeasible anyway, especially for a liberal-democratic agent, it would throw society into chaos and/or end up creating an extremist regime that is inevitably going to produce just as bad or even worse abuses than the ones it seeks to avenge (cfr. the cases of French Revolution and the Reign of Terror, the Russian Revolution and the Red Terror, the Islamist Revolution in Iran, the Morgenthau Plan, Mugabe's Zimbabwe, etc.). Absolutely none of the catastrophic backlash you describe took place IOTL, hence I am driven to dismiss your argument as (your usual) baseless and widely exaggerated anti-German fearmongering. TTL reaction to German rearmament and prevalent interpretation in the Western world of Nazi crimes as the main responsibility of Nazi specifically with limited blame for ordinary German soldiers and civilians is going to take place relatively flawlessly, much like OTL. Certainly no one of the vast majority of Western Europeans that got loyal to their bloc because of the Marshall Plan is going to switch sides to the Red fifth column because of it, nor are the Americans, British, and French to turn on the Germans, when they willingly went along historically. Absence of the Americans in the NATO system is going to be balanced ut by the fact German rearmament takes place under Pan-European leadership and not a national one. And for the record, if OTL circumstances hold true as they likely will, pretty much all the formative period of TTL EDC/EU is going to take place when the Tories are in power.
IOTL, revision of historical prevalent opinion with emergence of greater awareness of Wehrmacht responsibility in Nazi crimes and suggestions of collective responsibility of the German people (as highly questionable, unfair, and dangerous the very notion of collective responsibility is) was almost entirely a post-Cold War phenomenon. It may or may not happen ITTL, but it it does, provided the Cold War lasts as long as it did, it shall still occur several decades after establishment of the federal EU and its assimilation of Germany, when the last living witnesses of WWII are coming close to the end of their lives, and all the distance and scarce political impact this entails.
If you ask my opinion about the German military resistance, I am going to state they were no less the heroes for being genuine German patriots that tried to ensure end of the war left their nation in a decent place, and sought to spare their people from ethnic cleansing, extensive territorial losses, forced political division, imposition of a Stalinist regime that was just as bad as Nazism, and the war crimes of the Red Army. They may have acted far too late and too hesitantly, they blundered it in the end, and their notion of a feasible peace deal was largely exaggerated at that point, but their heart was in the right place and they acted for the greater good of Germany, Europe, and the world when tried to ensure the war would end with a year earlier with the Iron Curtain on the Vistula-Danube, all of Germany with 1938 borders being included in the Western bloc and being subject to the W German treatment, not to mention half of Poland, Czechoslovakia, Hungary, and Yugoslavia being on the right side of the Iron Curtain, as well as WWII damage and Nazi misdeeds being substantially cut short. The fact WWII did not end that way is one of history's big tragedies.
When the 1960s changes took place, the W German counterculture did pick responsibility of their elders in Nazi past as one more excuse to rebel and stir up trouble, in the worst cases up to indulging into far-left exteemism, chaosmongering, and domestic terrorism, much like their American counterparts used the Vietnam war as an equivalent excuse. However, pretty much the same generational polarization and radicalization pattern occurred throughout the Western world, even when the involved nation had no such skeleton in the closet. It did not make any difference, the radicalized youth took the same attitude and did the same things. Hence, what you mention won't make any difference. If the EU does stumble in its own Vietnam quagmire (possible but unlikely), then you shall have the counterculture radicals picking one more excuse for their trouble, if not they shall embrace different excuses. They were already calling anybody that did not agree 100% with their agenda a 'fascist' anyway, so their nation having a actual fascist past or not made little difference. As far I can see, historical evidence about the Cold War totally disproves wild-eyed anti-German fearmongering and hatemongering was anywhere as popular as you argue.