when greater dragons were new I was using a provoke tamer to farm them. Some red attacked me when I was on foot and I was able to kill him with teleport, invis and provoke. he was a dexer, so he kept running all over the place. Each time he came in to whack me I would provoke another greater dragon on him and then invis or teleport to screw him up.
he kept jousting at me until 2 of the dragons simultaneously used a breath attack. That was all she wrote. He came back and I did it a couple more times
Provoke has limited usefulness in pvp, but it is almost never expected. As long as your target doesn't stay off screen for more than 10 seconds, you can just stack provokes on top of them.
I have found that peace/casters can do mediocre in pvp against dexers. A lot of dexers don't have attack macros, so they can get screwed up if you AE peace them out of attack mode in the middle of hard hitting combos.
Discord is only useful against pets and summons. A buddy of mine told me that the devs once made discord work in pvp, but they disabled almost immediately because it was way too powerful. Discord is the key to shutting down any tamer that is annoying you. When I battle tamers in pvp, I usually use a discord/tamer. I disco their pet and kill it with my pet very easily. Then I turn my pet on them.