Well, I'm not on there all that much, and I tend to be a bit more cynical over here and a bit more geeky over there, you gotta do what you can to survive!
Overall, you need to look at it from a sales perspective. Guitar Hero has become a massively successful franchise, Game music would be a nice addition, but it's obviously not needed to sell the game.
"Needs" is a strong word, I would not say that Guitar Hero "needs" VG metal, although VG metal would be greatly appreciated, like a little Black Mages or Castlevania Battle Perfect Selection or Guity Gear would be a nice addition. VG metal would just be a nice feature, not something that's "needed" or even an improvement.
Yeah, well... if metal fandom translated to metal talent, Satriani couldn't hold a candle to me. But unfortunately... not the case. If it were, I wouldn't be sitting behind a desk all day recieving calls from better musicians than I, relaying their phone calls to have their CDs made.
C'mon, cut me some slack, I've only owned it since it came out about... like... 11 months ago? I definately never played it non-stop, I'd say my Guitar Hero experience has come in short uber-fun bursts. I've beaten all but 2 or 3 songs on hard and a good majority of them on expert.
Then again nowadays I pretty much only play with friends who can barely get through the harder medium songs, so I've had no real reason to challenge myself.