I doubt it can return the monster to hand, due to the limitations of having to have no more than 8 cards in your hand. I was thinking it putting the monster on the bottom of the target's deck would be the best fix for Reverse Time.
It's basically the same..

Main point here is CARD ADVANTAGE.
Top, Bottom or middle of the deck, it doesn't matter, you STILL lose a monster and the amount of cards in your hand remains the same.
The fact that the card goes back into your deck for you to 'reuse it' DOES NOT benefit you in any way.

The amount of cards in your hand is still the same, and only cards in your hand matter (and count as an actual advantage).

I don't think Reverse Time is overpowered. I have never used a Time deck myself, and I have been able to consistently defeat a Time deck with Reverse Time and Eternity with an Aether, Gravity or Aether/Gravity deck.
My main point is that the destruction of the monsters in ALL the other elements is a lot weaker.

I mean, look at all the dragon cards for example.All of them are balanced in a sense, that for about 10 quantums you get about 15 stats.
Some dragons have more stats in DEF, others in ATK.
This is consistent throughout all the elements.

But when we come down to monster destruction, it's completely different.
Compared to "Reverse Time" cards like lightning, fire blast, freeze are useless.

If the game funcioned in a way that you could only use ONE of the elements, this sort of incosistency would be ok, because we would only need to balance cards inside each element (so some elements would be better at summoning monsters, e.g., others at destroying monsters and so on).

But you can use any cards in any deck.
For example, if you run a lot of quantum pillars and you need to choose which monster destruction to run, you will ALWAYS choose RT.