For UR spells in Limited, we're getting this nerfed Forbidden Alchemy. Not sure if this signpost uncommon is going to help all that much.
See you say 'nerfed' but the mana cost is a lot, lot, lot, lower. Granted, this thing has a pretty good chance of whiffing even in a deck with a lot of instants and sorceries, and doesn't fill the yard, either. Not my cuppa