Not a problem.
The unupped version would randomly shuffle the creatures already on the field. There would be the same number of creatures for both players, they would be in the same places on the board, and they would end up with the creatures just all mixed up. You could get creatures from your opponent, and they could get creatures from you, but there would be no chance of creatures going to currently empty spaces.
As an example. We each have one creature and flooding in play. You can play this card, and the creatures will be randomly moved to a place occupied by a creature. In this case, they would either swap sides, or not. Neither creature could land in a flooded area, because neither started there. The creatures could only appear in a spot already taken by another creature.
As an extension of this, no player may gain or lose creatures, as was something you said you thought about.
The upped version would basically collect all the creature cards and deal them onto the field totally at random, with disregard for who had more creatures, where those creatures were, or what is the proper location for them. Normally, each person will get half of the total creatures, but one side could benefit over the other (though this would be more likely to happen with fewer creatures.
As an example. We each have one creature and flooding in play. You play this card. The creatures will go to ANY random spot that a creature can take. I may get both, you may get both, one or both may end up in the flooded area. It would move them 100% at random.
The first would ask you to play creatures first. Sparks would actually be great to lay down in combination with the unupped version of this, though, which is nice to see, even if the spark doesn't cost any aether quanta. The upped works best if you have no or few creatures, just as your idea, but it doesn't destroy all the work your opponent has put in. It just evens the board, at least on average, which seems a bit more fair than one person playing nothing and stalling with dimensional shields while their opponent builds up, then taking all their creatures, giving nothing in return.
The unupped would have good synergy with sparks. The upped could be quite powerful with TU to normally give an instant creature advantage.
With this, I am unsure of if it would be good enough to drain all quanta or not, but either way could work, since it would obviously be powerful.