Here's what I'm thinking:
Limit the card to creatures. Either let your opponent choose how many creatures to send out, or send out all of them. You then send out an equal amount, a la SoBr. That way, you don't have to fiddle with spells and such, but you are limited in what you can do by what your opponent does or has.
That said, nightmare/fractal? does it break it, or does the requirement of three separate quanta balance it out?
Also, what if your opponent has no creatures? is the card wasted? It would make Precognition more useful, in my opinion.