What would a Spell Shield summoner spell have done to the game?

Imagine a brief Spell Shield on a decently long cooldown was introduced into the game. How would this affect the game?

How often would it be picked up? What lanes, roles and champions would pick it up? What champions, roles and strategies would be weaker or stronger because of this? How would it affect the meta? Any other thoughts?

My only thoughts is it would be similarly game-warping as Flash, maybe picked instead of Flash a fair bit, especially midlane.

Speak your minds!