Adding flavor to a game that consists of many different ways to play and have fun is never a bad thing. There have been plenty of suggested ideas and fixes to PvP to make it an enjoyable and balanced experience. Sure there will be people who can play this game indefinitely for what it is, but having that bonus feature that you can choose/not choose to do that offers a completely different experience just adds life to the game. Claiming the diablo series is never and will never be a pvp game is just limiting the potential of this whole franchise. I personally have been involved with PvP in multiple games and genres and have come across LOTS of people that would play diablo 3 if it offered a fun and somewhat balanced PvP mode.
My monk is on HC, and I'm running combo-strike unity and ally for the % dmg to proc weapon dmg. I sometimes swap out ally for sweeping wind for more fun, but I think this build has one of the highest dps potential that I've seen.