Agreed that Tony's descent didn't have the affect it should have. He comically hits rock bottom instead of doing it seriously. They show some signs on taking it seriously but it's done for laughs. Too bad...it would have been compelling to see Downey do Demon in a Bottle.
Did they Americanize The Black Widow? It's interesting because they really didn't need to. In real life, Russia is so paranoid they would absolutely flip out at the prospect of someone having a suit of war like Iron Man. Especially if he were American. They would go to work instantly trying to replicate the technology. Rogue nations would take a lot longer than countries like Russia and China in trying to replicate the Iron Man costume.