u know that most decks use x6 copies of the same card, and it isn't a huge restriction for instantkilling?
aether already has thunderbolt, the best damage/quanta ratio card in the game, i don't really think this is really needed, at least in aether
Aether Quantalize target creature that have another same creature copy in both players' battlefield.
this idea is better (in terms of balance), even if more expensive than congeal+shockwave, both twin universe and your card are in the same element