I feel like most professions are actually fine to some extend.
With few correct changes the meta could be stable for a while.
Warriors are definitely the most broken atm. Their passive healing whilst being able to 3-hit rather tanky builds is ridiculous.
It seems like Anet won’t nerf Healing Signet again, so my proposal is simply to make (Healing Signet is still to strong though, make it scale with healing power, and have a lower base-healing):
Adrenal Health scale well with healing power, and only grant a very slight regen without any. Additionally it could be an Adept Major trait, so you would have to choose it over Dogged March (still with the proposed nerfs, although the nerf should not be as severe).
Remove the adrenaline-gain from Cleansing Ire.
If an adrenaline skill is blocked/missed or evaded; lose all adrenaline without benefits from Cleansing Ire (depending on how the other nerfs would affect warrior, this or removing the adrenaline gain from CI could be undone, testing would be easy).
Pin Down should probably have either a higher CD or a slightly longer casting time as well. The telegraphing is okay on anything but Asuras however.
Thieves could need their evades toned down, but to be honest I don’t see them as gamebreaking. Their dmg compared to their squishyness is a fine ratio, if their evades could just be toned down. A suggestion could be to give “Withdraw” as longer CD. That healing skill is ridiculously good for a 15s CD.
Last fix I would implement is for “Signet of Spite” to have an increased casting time as well as a renewed telegraphing – I’m thinking from 3/4 to 1½. It’s simply impossible to dodge that skill if you’re playing against an asura, and it’s incredibly difficult against a normal sized human – it shouldn’t be.
As a general change, I would change “Might” to grant 35 Power and 15 condition damage, instead of the current 35 condition damage. This would punish the current might-stacking builds like Ele and Warrior. I like the idea of might being used for power better than for condition damage. 25 stacks would still grant 375 condition damage, which would be a total of 909 in a standard Ele build, compared to the 1409 it is now.
These are only nerfs, as a lot of underdog builds could use improvements, but I won’t bother writing them down here. Although “Time Warp” having a 210 sec CD is mind boggling.