Personally, I like this card quite a bit. Despite the initial gut reaction of the community to say it is a redundancy, I think it would serve a useful role in the game...
There have been several comparisons to RT, but I think this card effect is more feasible to balance than a mass RT.
Although in terms of resetting card to their original state, this and a mass RT are roughly equivalent, mass RT is harder to balance because:
1) Sending cards back to the deck means they must be drawn again (clogs the player's draw and leads to effective card advantage)
2) Sending cards back to the deck means they must be cast again (leads to effective quanta advantage)
3) Sending cards back to the deck means that, for more than 1 card, they will not be available for use for several turns.
So in essence, this card is much less powerful than a mass RT.
-It does not provide card advantage,
-It does not provide quanta advantage,
-and, it does not postpone damage / ability uses.
On the other hand, this card has one advantage over a mass RT effect that I can think of right away. It is excellent in combination with other mass CC effects. For instance, it can remove buffs on creatures that would let them survive an AOE attack.
E.g. whereas RT favors cards that allow repeatable single target effects, this card would favor single use mass target effects instead. This provides a nice thematic distinction
I think perhaps the best way to implement this effect, however, would just be to reset enemy creatures to their base card state. This avoids having to specifically what is and is not an unnatural boost.
All around I actually like this mechanic idea a lot.
It is easier to balance than a mass RT effect would be, and it is thematically and mechanically distinct.
I would rate this as 4 out of 5 stars right now. The only reason I don't think it should get 5 is that it is a bit inelegant in talking about 'unnatural boosts and effects' and would be better off just reseting creatures to their base card instead. (E.g. the creature just reverts back to exactly what it would be if cast from your hand)
Also, I think the damage effect is not necessary since
already has thunderstorm for that...
Lastly, I think one very useful utility would be to allow this to target a player instead of just affecting the opponent. Assuming you intend this to also remove freeze and delay as well as stat and ability changes, then this would be an awesome counter to those effects if you could use it on your own creatures. I think you would have a really great card then!