You also leave yourself vulnerable to nightmares... kinda has a built in counter already.
Granted, a single counter doesn't keep it from the potential of being OP, but it does at least make users pause and think "what would happen if my opponent has a nightmare in their deck?"
I think the high burst draw power is pretty well offset by the auto-discard effect.
If it still needs a little more balance, it could have "absorb
per card drawn" or something like that.
Then it effectively becomes like a mass hourglass in terms of cost per draw efficiency... you could even pull down the casting cost a bit as well.
At any rate, I can't give a star rating for this card, but I think its worth much more than 2 stars... I'ld give it a 3 or 4 out of 5 myself.