DK's after that mages, after that paladins.
Tough call. For me it is a tie between mages and DKs. Take your pick removing either from wow pvp would make it a better experience for everyone involved.
I play a Druid and I hate pvp, so I'd ban Druids so I don't occasionally feel like pvping
I'm glad to see that shams are not being voted for.
I choose Hunters, As I ussually kill Mages & Rogues easily .