To offer feedback as to why?
You took a fun kit where resource management was meaningful and required an actual degree of skill and turned into a hot mess of 123's atop a couple GCD's that is part warrior wannabe, part dumbed down to heck and back, and all unfun.
the new TBN? You crated a skill that actively works against itself and the kit. Trash mobs under 3 can't dent it, in boss fights i've seen only tankbusters come close, not even roomwides will. But if you try to get enough mobs to do so you've now got nothing to fall back on because of that insanely idiotic nerf to abyssal drain. Which has become a joke power every 60 seconds for a meaningless amount of heal in any ST situation, looking at you bosses. And against a large pull you no longer have it's spam with quietus and a real resource break for TBN into blood (read your own lore btw!)
Delirium is a clunk mechanic thats oh look, i get a lil extra dps, and 200 mp per blood spiller is utterly insulting. The only thing worse was reducing quietus to single target regen status, and making us need to burn a GCD to get that equally joke 600 back. When compared to the cost of TBN and the maintenance buffs, oh i mean flood and edge.
It won't keep you or TBN up, unless you burn blood weapon at the same time which takes care of your sustain for the next 60 seconds.
So you need more mobs, but with the inability to spam abysal or TBN any more due to the break giving DA instead of blood atop the quietus nerf, you can't actually survive against the amount of damage needed to use it for it's main designed intent. Even if you do break it it's a 0 gain situation. You get a free hit, but if you're healer has half a brain you may as well just spam flood and edge anyway, because they'll be keeping you up.
Even if it does break the increase is may as well not be there. 1000 extra on my highest 600 potency attack? Really? Really? So again what's the point of new darkside if new darkside has no meaningful impact? and at least ninjas don't need to burn 1/3 of their resource bar every 30 seconds for an armor crush. and ninjas at least have more than one combo still!
As for flood and edge? utterly unimpressive in terms of visuals. You still have the dark passenger animation and scourge laying around. How bout them instead of imma poke you with this speck of dark around my sword? It feels like again i'm working against my kit instead of any kind of flow. They aren't attacks, they're a button i push every 30 seconds and praying i have enough MP scraped up from my 123 pokes.
Carve and spit gets a dishonorable mention here as well, at least before it's do i want MP or do i want damage? Now i get the worst of both worlds on a 60 sec cooldown that gets me 600 mp, and only 50 more potency than a souleater? Yay?