It seems like they've taken the usual formula and just stretched it out over two movies. Most superhero movies have a moment where our hero is down, and all hope looks lost... only to bring it all back from the brink. So, part two it is.
I've come to accept the Marvel movies on the basis that they're a giant subsidy program for the industry at large. Talented actors and directors can phone it in and make huge salaries, which enables them to choose an interesting, low budget project next. I'd still rather those low budget movies got even a tenth of the budget that the average Marvel movie does, but oh well.