Well, we don't have to do the whole chapter over. Can just do the castle again to beat Doom (and you get a free starter hero for finishing the story, too).
Well, I got a pre-order premium pack for $60 (though it was actually a gift, so I paid $0! haha). It came with Cap, Iron Man, Hulk, and Ms. Marvel, along with costumes and lots of G's to buy more stuff. I used some of the G's from it to get Spidey, Black Widow, and Wolverine (while he was on sale). I picked Hawkeye as my starter and got Scarlet Witch and Storm as quest rewards. And I got Cyclops as a drop. Well, PvP isn't done at all yet, so there's not much interesting stuff to do there. But group missions are fun and the daily missions can be fun, too, though the daily missions re-use lots of stuff from the story. You don't have to be 30 to do any endgame stuff, though. The lowest terminals are designed for level 27, actually, and it's not like you can't beat them at lower levels.
I don't really have a least-favorite hero, since I only got heroes that I like. It's not like I'm gonna pick a character I don't like, you know?