So the idea is supported, just not balanced.
Correct.
However you will still need to:
Balance it
Justify "why entropy?"
Justify "why temporary creature control would benefit the game"
These questions need to be addressed even if we agree.
I doubt it would fit as entropy as it runs on luck, infinite probabilities (randomness) and disorder, not direct manipulation of senses or subconscious as that is a direct approach rather than a random one, and it isnt associated with disorder because it only has one direct stage in mind control, not a disorderly function which leads to it.
so my vote goes to
which is the element that is associated with the hypnotic, manipulation/dulling of senses or subconscious.
direct temporary creature control would benefit the game because concept wise, it needs/lacks it. mechanically, it is basically a temporary PU but that leaves teh opponent without their creature. This can be done a max of 6 times to the same creature if targeting it. so in total, you could have control of it for 18-24 turns. But thats only if you are able to draw a all of the same card from your deck. I say lowering the max turns so that it doesn't cause that spamming problem, however the cost has to be lowered aswell so that it is still efficient. But that can possibly make a cheap temporary PU which leaves teh opponent without a creature temporarily. I'd say this is the main reason that mind control is not often supported. But concept wise, i'd say tis necessary, especially in an element that specializes in the manipulation of senses and the subconscious,
Darkness.