Hey, i'm mostly (stamina sorcerer, where are you?) a blade main being both mag and stam in pve / pvp for quite some time. There will be a stream of consciousness i guess.

- Btw all this is my own bias and ofc feel free to not agree and shake your head on everything you reading. I'm not a self-proclaimed forum expert but just a man who plays in free time available and loving it. Aaand my english is ****, i know

So. Playing dunmer both specs i've never was addicted to redguard/altmer(and now breton) sustain and was forced to manage my resources properly in solo pve (dungeons/wb's and vmsa), vet trials and pvp. All the cost additions from previous patches (merciless/relentless, execute and so on) was l2p'ed but new grim focus is almost not worth using at all, on a 80+ parse the skill versus some passive slot one makes 1-2k difference (can be more with 90k+ and not 200+ ping) but makes room for casting more potent skills and makes sustain less of a problem (loss of endurance, even this amount can be felt actually on practice) and rotation becomes just boring mess as it's on some other classes (stamina sorcerer, i'm looking at you if you still exist for ZOS *sigh*). Or i can still use it to roleplay complicated (?) dynamic rotation but the cost is too much for what i'll get. Results ofc will be different on other skill level of exact players.
Before the changes you had something that you have payed resources for - ability to went from combat prayer or not wearing slimecraw, go do some mechanics withour really losing much offence from stacked group buffs. Same thing with surprise attack, you were able to went from your healer to do stuff and not being in need of tank to fracture everything but helping and being independent.

I can argue that we still need that 8% but if we've completely lost it to the nerf treads and making everyone happy we should not lose some built in sustain attached to it and heal feature is not even close of a compensation for all we have lost. Damage is too high? K, lets give it some utility like giving mag/stam on hit or some other (de)buff (one can dream of fracture Damage is too high? K, but we have so potent and much used Mark in this OP toolkit /s).

Arguments about heavy blades or gankers are quite misleading imo, as all the changes are promoting more heavy+s&b playstyle, you'll retain infinite defile and a fracture while being armed with some new debuffs as Minor Mangle, Vuln on top (slot some fresh lingering+heroism pots for flavour if i remember correct effect of new alchemy ingredient) in a toolkit to make life even easier. Slot low slash for more giggles.
Dark cloak was core issue for heavy? Not really, it's more of a heavy armor easy health stacking/tk problem but now all those 2-3 NB pve tanks remaining are in a questionable position to say the least.
Incap losing defile will never be a problem for heavy blades, why give other pretty unique debuff on top of Reverberating spam? Plus we'll see a lot more talk around tanks and healers in pvp due to medblades not able incaping them for you. Best decision imo was to reduce defile time but who am i to judge.

Don't even want to start on magblade state in pvp, probably it was totally forgotten.

And how it all will affect trial score pushing groups burning Rakkhat on pad 2 with 8-10 necro or solo/duo youtube gankers and 1vX'ers? Right. The only big hit will be on vMA pushers (welcome to nmg club), solo pve, 4 man dungeons/arenas, progression style groups (vAS+2 especially) and unexperienced (or just light, medium, dw+bow running) pvp players. I hope this will be at least a bit addressed in future pts iterations.

More of a vent than a discussion but thanks for reading and please feel free to sound your opinion on a subject if any.
(or bash me)