I just did another Heroic CoS run, this time as 51 point Surv. From 2k DPS the other night, my damage in this last run fell to just under 1200; a drop of more than 800 DPS.
However, here's the reason why. In that run where I got 2k, I was using virtually nothing other than Volley. At the moment, if you're not Beast Mastery, your damage is pretty much entirely based on either Chimera or Volley.
In this run where I got around 1190 DPS, I trap danced, kept Serpent up, and was getting Lock and Load procs pretty much all the time; so if I wanted to use ES, I literally didn't have time for Volley, and even if I did use Volley, my damage from it was down radically due to no longer having Barrage or TSA anyway. ES, however, in its' current form, is just too weak.
ES' coefficient being raised to 18% is not going to make Survival overpowered. It will make us competitive, and in terms of raw, direct damage, it will be literally the first time in this game's history when we will be.
During TBC, Expose Weakness was advocated as the reason for taking a Survival Hunter, but it raised everyone else's damage, which meant that a lot of the time, we were still behind. The reason why we need that 18%, is because aside from traps and Serpent, which everyone else laughs at, that 18% is almost all we have. We don't have BM's speed, or Marks' RAP bonuses. LR and EW alone don't go anywhere near far enough to make us competitive with other people's damage, and truthfully they never have.
The other point is, Survival isn't a stationary tree; stand and fire largely without moving might be the BM or Marks playstyle, but it isn't Surv's. We need an ability which synergises with what we do; kiting.
It's been nearly four years, but I've had a funny feeling for a while now that WoTLK was going to be the expack where we would finally see Survival's true ascension. Assuming the ES buff survives the PTR, in pure damage terms, Survival's mobile playstyle is about to become irrefutably viable for the very first time.
I'm looking forward to it.