The way I see pvp ever since Doac, is the chase to fix op type's. Fix one (nerf) another type takes over.
Let me suggest a way to better allow fun play in pvp.
You have 4 class's, so lets go with, Tank, then wizard, ranger, and healer.
You would still have the ability to build your character anyway you wanted, but by declaring at creation you are 1 of the 4 type's.
This would effect certain abilities of your choice.
First let take the Tank, max hps 3000, no matter what you have as armor, plate being easiest to have max hps and cloth being hardest.
Enchanting armor and weapons helps and also would add to dmg medigation , health, magic, and stam regen.
Potions and food doing the same, but all scaled to your current lvl.
Leveling your pvp lvl would gain you other abilities.
Now the damage you do would be greatly reduced, by a factor of say 10, current 500 dmg, would now get you only 50.
By doing this, it would be much harder to defeat any one player, fights would take much longer. No one but the ganker crowd like's a quick kill, so it going to take a lot more skill to kill any one person, but it can be done.
Heck you might even live long enough to doing something besides lag out and die, some fun that is, not.
So as I said, 4 class's Tank 3000 hps max, Healer 2500hps max, Ranger 2000 hps max, and Wizard 1500 hps max. All dmg reduced by a factor of 10.
Except the siege weapons, they would still do standard dmg, as they should.
Only reduced by your support spells.
Last but not least, give everyone the ability to either turn on or off all spell effects.
That alone should help each player with their lag problems.