Hm, that might work. Sure, if it had a cooldown of 1 turn, you could still pump out a max of 3 sparks a turn and be very hard to get at, but that just means your opponent needs perm control. It's not exactly a fast combo, but it's not slow either. Packing CC might be just as effective, which is an indication it's balanced.
I can just imagine having a lot of fun with this, pumping out sparks.. I guess it shows I like the combo, no less so when you consider my Undead Thunderlegion deck.