I dont think it would be bad for MNM or GR in general, if anything sales would probably skyrocket, and to hell with WotC, they screw up everything they touch anyhow.........
I think Marvel would be awesome as a SETTINGS book for MnM, not a replacement game book, just a settings and adventures book.
As far as HERO being up there, I dont see how, the game has massive learning curve and takes forever to get ready to even play, its probably held on because allot of brain dead idiots wont give it up. Their universe is very bland IMO.
MnM on the otherhand is well done and really great at pickup gaming, unlike HERO/Champions. I was just saying I think MnM and marvel could go very well together, and if GR wanted to, i bet they could out-talk WotC at Marvel with a solid rules system, compared to WotC "umm how many supers games have they done", oh yeah ZERO!
Oh, well I'm just ranting and hoping for something that will never occure, I guess.