Since pvp is only wanted from some people you can make x-faction pvp.
it has been added from blizz as well.
This will help long queue from both sides to be eliminated.

P.S Perhaps you can make bots ( i am not so sure how this will work)

Please make achivement acount bound. It's hard to find people for some achivements to do it once, think about doing it on 4-5 different characters u might have. Also mounts could be account bound for the same reason. Some people have only 5-10 hours of game playing so this could be really helpfull. ...