I like Casey's background fine, I just think the way he turned out in the actual game was kinda meh. Maybe it was just the actor; I dunno. I agree with you about the torturing of Maestro, and I think it would have made the war that much more meaningful to Casey if his best friend also ended up dying at the end, as the original story synopsis said.
I do prefer the "son of Iceman" concept over the "abandoned GE experiment" one, though, that's for sure. Still not a big fan of "Lance;" couldn't they have come up with a better name? What does the R. (his middle initial) stand for?