I like the concept though. Something like:
Inquisition is turned into a debuff on targets. It hits every target around you (8 yards or something) and applies a dot on everything hit.
You can then activate the skill again to absorb all of the debuffs, gaining the current inquisition buff for x seconds (x=base value*mobs absorbed).
Think something like this:
Scenario 1: Single Target. In this situation you want to have the inquisition on yourself
Scenario 2: 4+ Mobs. In this situation you want to have the inquisition debuff on your 4 targets.
If it had to be a cooldown, they'd either need to buff inquisition and make you unable to have 100% uptime to compensate (Think Tiger's Fury for ferals sort of style) or the cooldown would have to be short in order for the debuff to be useful for aoe (Think galakras waves. Imagine if it could not be up or every wave).