There's a sprinkler analogy that exists for this issue.
Let's say you were to buy a new sprinkler for your garden and one day, you get told there's easily a better place to put it in which will make sure all your grass is correctly watered. Great!
Except you don't want to move the sprinkler because you put it there yourself - you instead look at the water pressure, the trajectory of the water, the type of grass you have. etc etc... when all you really have to do is move the sprinkler.
This is what's happening right now with class balance in PVP.
"MCH too strong in PvP? Buff BRD some more np they'll learn how to play" - SE
BRD can already guarantee a kill on someone in ONE GCD from 80% every 2 minutes if they have a single crit. If not - just hit Misery's End to finish them off. MCH takes more work but can perform even better in the burst if BtE crits.
Also - DRK still needs a damage buff, although in my opinion only for the small burst window. Sustained DPS is not too bad as they have other utilities but PLD has the utility advantage by far and WAR just outshines it with double FC's.
I would simply propose these changes for example:
Barrage hits 2 times instead of 3 times, given the current changes. Can still kill from 80%, more reliably from 60%.
Nullify BtE crit chance - MCH has a higher skill curve so I think no other changes are needed.
DRK Carve and Spit - Potency to 600 (PvP only)
The reasoning for the C&S potency change would be so they have a 1500 potency burst . WAR's have 2000+ potency, including the stuns and Storms Eye in beserk. These figures are not even including the vulnerability debuff - which actually gives a WAR a 2500 potency burst and DRK as 1700 burst. It's just enough to be able to harass a player.
I think the Sole Survivor buff is actually pretty good. With a DPS buff it will actually put DRK in a worthwhile position.