Cloak of Kabum

How would you feel if warlocks got this spell trainable at lvl 66?

Cloak of Kabum:
1 min CD
Insta cast
300 mana
CoK reduces the physical damage done to the warlock for an additional 90% for 5 secs
CoK reduces the probability the Warlock gets stunned, gouged, blinded (and any other disorient/snare effects) by 90%
CoK reduces the chance of spell interruption by 90%

If the warlock learns CoK he can not learn Death Coil !!!

I would go for it. Do you think it would be OK for rogues or it would be ... say... slightly overpowered?

(soon will also post in the suggestion forum. Just want to gather your opinions cause it could be to much for all warlocks get this spell at lvl 66.. dunno....)

EDIT: correction to the spell description