I Have played several games where pvp was a big part of the game .. but generally most players are "care bears" and prefer it in it's place and time ..Most people also prefer some type of reward for pvping.. and even if they arn't die hard pvpers ..if the rewards are good they will pvp.
so here we have D3 where at release ..Arena will have no rewards besides achievements. some people will play for fun.. some will play to get the achievements.
But i personally feel that it will not provide a long term pull for pvpers.. I know the game will not be an esport..But in many games it is the pvpers who spend the most money when they can. so if bliz want the rmah to be more successful .. adding better more interesting pvp modes with some kind of ranking system and some kind of rewards .. that push more people into useing them ..
lets say there is a devision system that works based not on total winns or losses but ..sya we start out at division 12 .. and to get to devision 11 i have to win a several games in a block of games.. and if i get to 11 and lose several games i move back down ..no permanent point system. so you are working your way up based off your skills and the luck of who you get matched against..
now with this system you are always open to teaming up with people who are close to your division .. so if you are in devision two and your fiughting someone and he is really good .. you can contact him after and team up with him to own if he thinks your good too ..and you can build teams fluidly ..and as you get into higher ranks the balance comes from everyone knowing how to use their skills and what works best.
as far as rewards go as you get into the more advanced ranks.. players can drop different kinds of loot randomly ..or games can give points that can be used to buy pve mats..runes and gems ..but not gear ..