By the Dark Knight treatment, I mean what happened back in Stormblood to Shadowbringers, where all of Dark Knight's sustain went out the window the next expansion. I get that Warrior is supposed to fight with their HP along with mitigation, but I'm going to bring it up again that healers have been being pushed out(in a minority) just for speed clears.
If I'm going to be honest, the reason why everyone plays Warrior is because they're not just the easiest tank, they're the BEST at everything. Sustain, mitigation, and also having the shortest CD Invuln puts it in a spot where while it's not the highest damage, it brings every utility under the sun that isn't Raid-wide Magic Mitigation(and outshines PLD in every regard nearly).
90 Dungeons are being dealt with by a 3 DPS/1 Tank squad, and it is only because Bloodwhetting is a 1:1 recovery, akin to old Abyssal Drain for DRK back in Stormblood. You had essentially infinite MP through Blood Price(getting hit gave MP back back then before they removed it) and could spam Abyssal Drain for HP to be unkillable in large packs; however, it wasn't ideal for single target.
As for Warrior, Bloodwhetting is ideal for EVERYTHING. Single Target, AoE? Doesn't matter, just do damage get HP back and be a self-Benediction. What's more, this is on a 25s CD for something extremely powerful that is supposed to be a tertiary cooldown.
So, there is only one way to fix this: cut Bloodwhetting's healing IN HALF. It's essentially what happened to DRK when they got thrown into Shadowbringers with AD being really weak on healing. It'll also put a stop to current patch Dungeons being done by 1 Tank/3 DPS since your sustain isn't insanely good on W2W.
And yes, I get this may seem "anti-fun", but it's to a point where it's breaking the Trinity alongside other things that are phasing out Healers. In Dawntrail, they need to address this issue directly if they want the game to live since a lot of people are hinging everything on Dawntrail.