Well from my point of view, I agree with Lance here. Power Mimicry might have a place, power absorption would not.

Power Absorption is like... Majin Buu territory. Let's not do that please.

Mimicry though... I could see it like a Mystique-like character that can mimic whatever body they take on.
Or maybe a mirror effect?

Or maybe they don't copy the powers at all! It's just an illusion!

Godang. How many mimicry type powers are therrrreee.