This is easy.
I would remove any cross over whatsoever between PvP and PvE. You say one skill? I say all of them. You want PvP? Here ya go - these are your abilities and what they do.
You want PvE? These are your abilities and what they do. This segregation is LONG since overdue.
hmm 'skill' - all non-healer self-heals (except for things like draenei racial ofc)
I'd like the Ring of peace removed, or atleast, redesigned.
Stealth/Prowl. Vanish would be fine if it remained limited.
Keep in mind that I'm a Rogue. Stealth gameplay creates massive balance issues, and I'd rather my PVE not be messed with because Stealth is good in PVP.
So, yeah. I'd rather Rogues not be balanced around getting the opener. I'd rather Stealth be a limited mechanic tied to vanish.
Steve Irwin died the same way he lived. With animals in his heart.
Blanket silences, and to a degree, normals ones to.
I hate being stunned, trinket, poly'd, finally start to cast a single spell. Bam, 6 sec silence.
As an ele shaman: Shuriken Toss, Paralytic Poison or Garrote Silence. Rogues since Cata have been so frustrating to play against, CC and damage just up the wazoo.
Another candidate is Solar Beam + Ursols Vortex, that shit is just so broken - 5-10 seconds of being unable to do fuck all while they blow 3 damage cooldowns together and zerg you down in seconds with absolutely nothing you can do about it.
Fears/Bubble/Mass Disarm
Solar Beam-Vortex combo | Ring of Skill | Fists of Fury
Untrinketable CC is just about the dumbest thing they could have put in this game.
Remove Sinister Strike. I hate the noise it makes.
That annoying hunter's spider web.
that aoe stun/slow shit dk's have. (remorseless winter?)
Omg, so much to choose from!
I do find deterrence to be annoying too, but it's only for a few seconds anyway.
Ring of Derp
Roots. Roots all over the place. Roots lasting an eternity.
Deep Freeze.
30 second cd stun that allows the mage to auto crit with pretty much every attack they use. Totally balanced.