I see people complaining all the time about specific things in PvP, so I would like to ask the community what changes they would make if they had the chance? Before we have PvE QQ'ers coming in here, these are STRICTLY for PvP only, not for PvE. This is if we could make changes to the class in PvP without having adverse effects on PvE.
What I would do is...
Deathknights:
DoTs can now be applied through AMS, otherwise acts as normal.
Glyph of Anti Magic shield changed: original effect + Magic-based DoTs cannot be applied while AMS is active.
Druids:
Faerie Swarm slow reduced to 30%, down from 50%.
Hunters:
Number of abilities that can be cast while moving reduced; can still attack while moving.
Kill Command can now only be used while the Hunter has LoS to the target.
Mages:
Ice Lance now deals 3 times damage against frozen players, down from 4 times.
Monk:
Disable can no longer be used to root a target, slow is reduced to 40%.
Rogue:
Burst of Speed given a 15sec CD.
Paralytic Poison now DRs with Kidney Shot.
Sub Mastery bonus halved while in PvP.
Warriors:
Critical Strike damage reduced to 175% from 200%.
Bladestorm damage now deals 40% weapon damage every 0.5 seconds, rather than 100% every second (14.4% or so decrease in overall damage).
Bloodbath double dips in PvP resilience (initial damage is reduced, as well as DoT applied; not sure if this already happens. If so decrease the DoT damage by 5%).