1. It would 'split the userbase' as much as any other playlist made along preference lines (it's just another playlist)
2. This was a response to the strong annoyance expressed at people playing for achievements and ruining the games for people who weren't. If they'd rather keep playing with those people, then why complain? The only solution is to stop them playing for achievements (cut it altogether) or let them keep playing in another playlist. Else, complain for the sake of complaining.