There aren't enough "copy target spell". Instead of trying to copy one big spell, this makes any spell come all at once. I considered "the next spell you cast this turn has replicate" but decided keeping to one mana was sufficiently interesting by itself.

It's possible it shouldn't be open-ended, even "copy twice" might be good, and this is very very good if you can copy lightning bolt or shock.

Also Ancestral Recall ;) Even Ponder or Serum Visions is pretty strong.

I don't think this is the broken half of the "ancestral recall - something else" combo :)

But yeah, even if it's giving up two cards to play mind spring, it's a lot better if you scry before every one. Maybe I should start with a simple "Copy target CMC1 spell twice" which would still be quite interesting, without being as open-ended.