On Paladin and Dark Knight, it doesn't matter too much - most of Dark Knight's AOE is magical and DA-Abyssal has lifesteal and on Paladin you have Clemency if you need a good chunk of HP really quick.

For Warrior, there is a couple of problems that come up if he had Blood Bath again:

1.) Berserk boosts physical damage and Warrior is all physical. From spammable Overpower, to overzealous healing Steel Cyclone to berserked hexa-decimate, the options are massive and heal an unholy amount.
2.) With Equilibrium and ToB you already have some heal options. If you gave Warrior Blood Bath, imagine the sustain from the IR-serk combo.

While it was handy to have (and did a fair boost in enmity when dealing damage with it), I don't really miss it.