There is a theory I hold faith in that has always performed true. In any given team, the players on that team only perform as well as their weakest members allow them to. (ie. If 1/2 of your raid in DPS'ing lower than the enrage timer, the other 1/2 only do slightly better, because they don't have to do better than that.)
What does this mean? It means simply that if you surround yourself with better players, you become a better player. If you moved to a server where everyone is better, it will give your raid a reason to pick up their socks and do better than that.