Uh. You don't think there's multiple story threads to tie up? Characters who need resolutions? Dealing with the aftermath of IW to give the movie proper dramatic weight? Infinity War gets its strength from everything you just mentioned here and you expect the finale to have the emotional and narrative weight of the original Avengers? To just be a dumb fun action flick?
Again. This is a send off to an 11 year, 21 movie cinematic endeavor with many character threads coming to a head. They're gonna go big.
I'm kind of expecting the narrative events to eat up the bulk of the time, not the themes/tertiary story threads/character resolutions (which don't seem big enough to warrant extensively ironing out, beyond a few minutes here and there). They'll probably focus on one big thematic idea and just briefly touch on other tidbits as satisfying nods (like they've been doing throughout the franchise)-- I'm not expecting them to EXTENSIVELY iron out things like Iron Man/Captain America's philosophical differences beyond those kinds of brief moments, for example. Narratively, everything seems concentrated enough on a practical level that even if you tell a story with emotional and narrative weight, I wouldn't really expect that to add up to three hours, personally. Whereas with Infinity War, I can at least see the argument that there's just too many completely separate things going on in different places to feasibly tell in a short amount of time without feeling rushed.
Again, I'm not saying it COULDN'T warrant it depending on what direction they go in (which I agree, could be anything), but based on the setup, what we can currently expect, and what we think is necessary, I don't really see the evidence/expectation of it, at least not enough that two hours would be seen as questionable or too short.
I'm not sure I agree that how long of a cinematic endeavor something has built up to means that it demands to have a longer runtime to be properly resolved anyways. Something can be tight, economical, and satisfyingly concluded without being a dumb fun action flick. It seems like a bit of an exaggeration to begin with anyways, because traditionally, big dumb action flicks without any weight aren't ideally two-hour movies anyways, they're way less than that.
I especially don't think that's the case if that increased time is spent on extra jam-packed content rather than on slowing down the actual pace (I think that could arguably add more weight to something, but if I'm not mistaken, that doesn't seem to be the argument/expectation).
But that's just my impression. It could work, but three hours seems like a long time even for things that have a very slow pace. I can think of exceptions, but even with the Lord of the Rings movies, I don't think of them as examples of necessary three hour movies. I would also say that hypothetically, I don't think that Godfather 3 necessarily demands to be any longer than the first two movies simply because it's the conclusion/resolution to something really big, personally.
