Motto on your first point. We make fun of Peter for his angst, but he just visits that gloomy state periodically, Matt (since the 80's) has pretty much set up permanent residence there. That's just how he is, and a lot of his gloom and unhappiness is self inflicted, but he can't really help being that way. He is a hero, but he always finds a reason to come down on himself, and if he can't find one he almost seems to manufacture a reason through his behavior or perception of himself. That does mean he's inclined to be a self involved dick at times and while I wouldn't say he's necessarily self destructive he is complex.
I just wish there was a bit more of a balance. Cheating on Milla was a real low, I'd like to see the next arc/storyline be something a little lighter and genuinely heroic, just so Matt can reestablish who he is as a man and what he stands for (before it all inevitably gets torn down again).