In WS Cap had to get to grips with a changing world where everything seemed permitted to fights threats (a nice and current theme). His own views on world peace and justice were very different as they dated back to the 40s. So he was somehow forced to find a way to stand for his own principles, his friend Bucky and the whole enchilada of Shield, whom he worked for and agreed with in principle in fighting major threat. Just not their means. Much more complex stuff going there.
Now it's just about Bucky (again, same thing as in WS) and this weird treaty. And... he does what he always does.
And them being split up in teams... here's the thing:
Spoiler:
despite the fact that there is something of a split (it seems even Stark has his doubts about the treaty now, so they're being closer again), most of them are locked up and they still like and respect each other. Steve's letter at the end proves that. So... here it is again: they may be physically split up, but character wise they are still very close. Which is my point: there's not much of a real issue. Or a real split. They are still the same Avengers. And I'm sure the next big movie with a lot op superheroes is just about them getting together again. Which makes this "split" quite obsolete as well.