I have it on both my characters, a STR-based melee tank and a caster.
It works well for the tank, but still there are plenty of threats besides bleeding and it doesn't offer total protection. And it doesn't work well for the caster at all.
If anything is broken about Leech, it's the way it interacts with Bloodletting. But again, it's only helpful for the tank -- if the tank tries to cast Bloodletting on the caster, I don't get that massive chain of small heals, just a single one.
