Only thing I hated about the first Avengers was how they made Iron Man make the ultimate sacrifice like it's his own movie, as if Iron Man is every audience member's favorite--he's not everyone's favorite. He's an arrogant, self-obsessed, rude narcist who thinks he's smarter and better than everyone. I liked him just fine with the exception that he did have a little too many perfections, genius, rich and famous. It was until Avengers when I hated him, at least just in that film. It should have been more centered on Captain America. He's the one was struggles the most, coming out of time. I think he deserves more credit than Iron Man. He gets picked on.
If Stark's attitude wasn't so arrogant and childish, I would have considered whether he should be upfront. First Avengers film should have had the climax be an ensemble fight rather than Iron Man making the last save. That was a total Joss Whedon preference. Several people including me, did not like that. It was because Iron Man is Whedon's favorite. I hated that they ended the end credits with Iron Man's light chest logo, when it should have been Cap.
Ultimatly, I find Cap more relatable than the all-perfect Iron Man.