Guild Wars 2

Theives rejoice at the thought of the following skill, a bandits true dream. Bandit Spirit! Utility slot skill: cooldown 90 Seconds. Deception type. Skill duration: 60 seconds. Ability: Cloak for 60 seconds while losing 50HP/S

By Cloak?
I assume you mean stealth?
I can see why you would suggest such a thing, however I do not see a reason for it sadly:
Please enlighten me ^^

I heard Guardians are supposed to be getting a trait thats similar, ‘’gain 10s stealth for every condition removed: Max 6 stacks, can only trigger every 45 seconds.’’

In all seriousness though lol, gain stealth for X seconds and lose X Hp/s does sound legit on a theif, :P