Common rarity, suitable for collection or gameplay
Aether Revolt has several powerful Improvise spells, and some are already starting to see a bit of play
Build your list in the deck builder, count your ramp honestly, and then watch your games: if you're regularly stuck on four mana while the table pulls ahead, add ramp
First, it's power and toughness are */* rather than */*+1
Delirium has proven to be something people can enable relatively consistently when they want to in the past ( Shadows Over Innistrad ), so with the right support suite, this card can just be Demonic Tutor a decent amount of the time
Vigilance and reach means this dominates on offense and defense, while ward 2 gives it just the right amount of protection to let it stick around for a bit