surprisingly the tailoring cloak enchant require 400 tailoring to apply to your gear which seems very odd. No imo the professions of choice for a pvper as my understanding goes would be
Alchemy- for the use of pots and say LOL at people who almost kill you before you do pot (bound to get nerfed or made for everyone and not BoP
Blacksmithing- Said this in another post regarding professions, but BS gives you a MH mace and a slowish 1.6s OH Dagger that are equal to what you can get in S5. Also BS can make a belt buckle and attach it to a belt allowing a new socket on the belt. Not sure if thats BoP though so maybe everyone can have it.
Tailoring??- I mean its a long long shot, the enchant on the cloak is nice 1000 armor pen is sweet, and if they are allowing the use of pots maybe just maybe they will allow the use of nets.
Engineering / Enchanting - enchants on rings for enchanters only (every little helps). And engineering gives some nice things + a sweet haste enchant on gloves but with a 2min CD.
I don't see much from other professions that gives you an advantage over someone who is not that profession.