I suppose if your opponents hand was 1 card or empty and monocolor this card could do a bit of damage. And its true it costs your opponent his/her next draw. But generally speaking I think this card is pretty worthless. Does anyone who really knows this game seriously use this? I doubt it.
Here is my suggestion, what ever element type this card is used on, up to 10 (tentative number) quantum of that type is removed from the opponents quantum pool. If used on a card that has no type, 6-10 (uncertain of what number to use) quantum of EVERY type is removed from opponents quantum pool. Which would set up a actual potential use for "relic" and unupgraded shards.
The start of your post would make it OP. On rush decks, the thought is to totally fill up the opponent's hand AFTER he rushed his hand away. Therefore, using the nightmare would make it impossible to be played, and even 'cause damage. That apart, it could just kill those good draws. I say no to the first sentence. To answer your question, too, I do use this card and I have played this game for quite the while.
The 10 quantum take-off from the opponent's hand is the most absolute fail, as in , Both for mono's and duos, you might just throw a other quantum type card into his hand and he will still even lose the quantum he had/needed to play. So yeah. It would ruin rainbows, by for
If it had no type, saying it would take 6-10 quantum of every quantum is MASSIVE OP. Up to 2 I even accept, but for a freaking 6-10, never. Yes, it would make relic's and un upped shards used, but imagine what it would do to lower cost cards. Ex : Quantum pillar. Yes, it does counts as a card.