While it's true that more running time =/= better movie and I'm refreshed by Marvel's non-bloated blockbusters I really hope this movie has some time to breathe.
What I mean is the number one complaint with pretty much every one of their movies since TIH is that they could've used more time, even just a little to flesh out some storylines/characters. I feel like they really don't get quite that much "breathing time" to just pace themselves a little calmer and not non-stop moving forward. There was a little of this in some nice scenes like Stark watching Howard's videos in IM2 and Thor having a beer with Selvig in his movie. But for the most part everything's just a tad too fast paced.
For example, in Thor him and Loki are being educated by Odin while young and we flash forward to the coronation. That'd be fine, but the way it happens sorta feels like (to me, at least) it just smacks you in the face with the music and big event happening after this more intimate scene, and not in a nice contrasting way. It seems there's a deleted scene with Thor and Loki before Thor heads out to showboat and I think this would've been nice to ease into it smoothly while fleshing the relationship out at the same time.
Another moment would be in Captain America where they discuss marching straight into HYDRA toward the end and Cap says, "That's exactly what we're gonna do." Then BOOM- Cap's riding a motorcycle into camp- which wouldn't be too jarring if it weren't for the fact that he was mid-chase with HYDRA soldiers. You'd think they'd have this cool "revving up for the mission, here comes the big third act showdown" moment but instead it shoots you right in there, and it takes a second to process. With a couple of preparation and "You ready?" shots the transitioning could've felt a bit smoother.
I loved the **** outta both movies, don't get me wrong, but some more breathing room in these films would be nice. It doesn't make it "boring" to have the movie chill out for a minute between big scenes. They do do this, I just feel not quite enough.