Well, here's the thing: In Guitar Hero III, Bret Michaels would come out and sing "Talk Dirty To Me" (except in the Wii version) whenever you played it. Since Guitar Hero III was only a guitar game, and there was no player-participation vocal track, you couldn't make Bret sing other songs. However, Tom Morello and Slash both were both unlockable characters in the game, and you could use them as your in-game avatar and make them play songs that they otherwise wouldn't ever play. For example, you could make Morello play the aforementioned Poison song.

When the decision was made to put Cobain in GH5, of course they made him an unlockable avatar. There was really no other option.

Berserk007 wrote:

although possibly lacking in the range of music this time around

One of the main complaints about this game has been that there's too much diversity.

Well, I think it serves as a good, albeit hard lesson for people who might be having suicidal thoughts. For many, suicide isn't just about ending what they perceive to be the intolerable agony of existence, it's about punishing those around them. It's about making others feel guilty for ignoring you or not treating you nicer. It's about getting attention, even though you're not there to enjoy it. This is not always the case, and it may not have been the case with Kurt Cobain, but it is sometimes the case.

If Kurt Cobain were still alive, he could have told GH5 to fuck off. But he killed himself, so too bad. This is the message we need to be sending. There is nothing glorious, heroic, or romantic about suicide. If you kill yourself, you won't get respect. You won't get dignity. You'll be turned into a fucking joke. And it's a good lesson.