Yow. That's one heck of an on-board trick. Way too good / board-affecting for common. Utter protection against removal spells and/or your opponent's attackers, just for leaving two mana up?

Better? It's Mother of Runes but with worse stats, an ability that costs , and can only target allies.

Adding alleviates my power-level concerns, yes. It's still the kind of on-board trick that Wizards don't like on commons because it makes the board more confusing than they like commons to do. Many designers choose to ignore that particular one of Wizards' design principles, though.

I'll use it sparingly at common, but as long as the power level is good here, I will keep this one.