Castle as villain?
Maybe the problem is in the villain. I think my major let-down feeling comes when I learn it's some random crime boss. I guess getting into WHY Frank Castle is the way he is might help, but it's also about, maybe, how this sort of justice isn't quite the same as Batman's, that they're both eager…

The room echoes, but whatever
Apparently Frey had a few gifts he wouldn't bother to tell others. I mean, whatever, I doubt any memoir is 100% truth, but he didn't even play by the rules and try.