I'd suggest something like a warrior, you will benefit from the user controlled movement if you pick a melee class and you won't have to worry about interrupting casts to move. Be careful though - doing rated pvp means you will be under a lot of scrutiny. For example, if you are instantly interrupting every cast then your opponents will probably catch on, the same will go for any instance of responding inhumanly fast to a situation; DK death grips, warrior charges, trinketing stuns etc.
example:
[video=youtube;bKSADTFZ9Gk]http://www.youtube.com/watch?v=bKSADTFZ9Gk[/video]
Just be careful in your setup and test it a lot before you go rated.