That's your opinion though. Having the sustain be useful in dungeons and raid settings whether it's from the AOE sustain or the barrier/mitigation potential, it's quite nice to have. It'd be a real shame to have it be touched, and there's far bigger things to touch really. Want to teach players not to AFK, there's been doom lately making the rounds since Fell Court of Troia since we moved away from the Bardam's Mettle puzzle boss style. Want to also not AFK, try content that's Extreme or higher and watch things get hellish if you do such a thing.
I can see where you're coming from but there's other ways to deal with it than harming a piece of kit. It's also just a difference of opinions at any rate, you don't like the sustain, I do, DRK is more for you then I suppose although unless that PLD status is old, maybe you prefer not as strong healing, fine by me but I got WAR for the big stuff. Some shifts include either adding some more elements to the combat design overall or giving something else to the other classes. Healer's should have that discussion on their threads, but I can say it's primarily their super boring "rotation" that's the bigger problem here. The healing is quite necessary for the actual hard content.
Bloodbath used to be a Warrior ability long long ago that was taken away and given to Melee's, which should get some good sustain since Second Wind is frankly near useless. Sure, you can maybe clutch survive one thing, but Bloodbath can do much much more. We don't need it now though, PLD has many forms of healing, WAR as well, GNB has a couple regens, and DRK could just use a reworked Blood Price. Melee and Tanks can enjoy the best of both worlds and I wouldn't want to take Bloodbath back from them, just give DRK something and maybe a tiny bit of help for GNB since that 25 second combo window is quite long unless you pop something before using it I suppose.