Hrm...I was personally thinking of something like RT, where you basically delay a creature for at least 1 turn, and deny the opponent the creature's casting cost.
This, would destroy the creature, while forcibly removing the creature's casting cost from the opponent's quanta pool.
In effect, after playing a 10 quanta dragon, if someone kills it with this, you then lose another 10 quanta. The upgraded DRAINS this, allowing for a nasty combo with Mindgate.
The playing cost of the dragon is not in my consideration. You can use a lightning to kill a dragon but you won't say that you use a lightning to deny opponent 10 quanta. Same for this card.
Don't forget that in an upgraded environment (both players using all upgraded cards), the creatures usually have more HP (even doubled in some cases) so they is harder to kill and the cost of Quanta Drain is also higher.
