In theory its a fun idea, in practice it isn't. I don't think any content should be gimped because you lacked a Paladin.
Now what I think putting it in practice here makes more sense:
Make our offensive cool downs defensive. Through damage we become better tanks.
Ie. Soul Eater's self heal currently.
Another one would be say dark arts with Bloodspiller puts a reprisal-like effect up. Dark Passenger's reworked as a mini debuff for bosses in mind. Heck it's in the name, throw a silence on Quietus.