Fenrìr wrote:There really is no ~best~ as in (A) profression is going to beat (B) profession in all situations. Engineering has it uses and probably does beat out the others, but truth be told, there isn't any that will make or break PvP / RBGs to the extent I think you're looking for.
While true, things like mining/herbalism/skinning aren't going to have noticeable improvements on PvP.
Tailoring is proc based (the cloak enchant) so unreliable for burst scenarios.
BS/LW/Ench/JC/Insc all give static boosts (though BS/JC allow for more versatility.)
Eng has a number of useful options (that do have drawbacks, like instant-death, that may or may not ever happen.) You get some versatility (armor/damage/haste for gloves, bubble/speed boost for belt, etc.) The biggest downside to Eng is that it doesn't get better throughout the tiers (goggles are still only 359 ilvl and the sockets didn't "level up" as far as I'm aware.) But that's really only a drawback if you consider the goggles a profession perk.