I haven't seen the film yet, so this post is pure speculation.
Cap was funny in avengers, but just kind of a rage filled poo in the self titled film, like he succeeded despite his efforts, rather than because of them. I didn't "buy" the interaction between him and agent carter, she just seemed like a beta version of black widow sent out to dupe a soldier into signing up for the supersoldier program. And then, after what seemed like two or three 20 minute meetings they're supposed to be besties?
I also didn't care for Howard stark being a beta version of tony. I prefered the captain of industry howard from iron man 2.
Anyway, the fun was gone in winter soldier, and poo really hit the fan, supposedly destroying the status quo, which for some reason, returns in ultron.
Seriously, networked heli-carriers with stolen stark tech were the big threat in winter soldier, not rabid pitbull bucky barnes. Oh, and lets reinstate shady poo Fury. Why not?
As far as I can tell from the trailers, Tony has sold out to "the man" possibly to avoid war crimes charges (Banners shitty AI coding vs. Infinity gem highjinks) set aside because ONLY THE AVENGERS KNOW THIS. Jarvis had anti evil protocols. Ultron? Not so much.
And cap wants to protect rabid pit bull barnes. For reasons. I can buy this motivation, considering what a madam movie Rogers is vs comic cap.
I'm not totally sold on Tony backing the man though, he spent quite a bit of Iron Man 2 fighting against stark tech being coopted by the military, and one of the baddies in Iron Man 3 was the Vice President of the united states.
So I buy the skeletor robot riot bots from ultron, not throwing all he eggs in the uncle sam basket.
Not sure where Igot the idea, but it kind of seemed like he was killed in the supersoldier process and then reanimated. Might have just been my brain misfiring.
Winter soldier was more of a movie. Made black widow and cap into black ops soldiers, which worked, but my mom wouldn't watch past the boat scene because of the brutality of the fight scenes. Clearly steve is repressing the poo out of his feelings, like how he jumps out of choppers and stays in his time capsule appartment
Tablet moved some paragraphs around, and I don't have a computer around to fix it.