As a warlock main, I'd like to support the ideas previously mentioned about elemental stripping being in EDs and mantles adjusted to support procs off blast! (And while you are at please please please fix the door barriers immune to blast - feywild and IOD I'm looking at you)
I've given the changes some thought and I'm going to switch away from warlock once I finish racial lives (11 to go!) as a result. While I understand the damage of Dragonbreath was deleting groups its not like casters are in a good place v. melee in high reaper. I agree with
@Ying 's previously posted summary of the impact on warlock play and we were already struggling relative to other casters (imho).
I'm not sure what the right decision for SSG here is but my biggest issue that casters level quickly but melee outshines them at endgame in both raids and reaper. So as someone who is on the downhill slope of finishing lives and getting to 156 reaper points this puts me in a tough place but perhaps this trade-off decision is WAI?
I believe at least the previous spell damage reduction at r7-r10 should be removed with U66. With melee damage where it is I'd like to see the caster epic strikes across the board be better (either via base damage or better MCL scaling).
Alternatively create an adrenaline / (old) hunts end equivalent for spells....