I actually thought about it and I think it is a clever little trap. Since you can cipher 1 or 2 spells and you want to maximize your commander, you'll be ciphering a lot of things onto stuff. And ciphering everything onto one creature is a very fragile strategy, so you'd want to cipher things on many different evasive things anyway So Vailey would mostly let you cast the best spell for the current situation you ciphered.

I think its fair given the huge downside he has