I agree with the guys up there, it should protect only permanents, and maybe only one per turn, something like the guard skill is now, but instead of stopping an enemy creature it'd protect your permanent, in that way it could have a lower cost, I don't see why it should use aether in that case tho.
Why:
Quinting already exist, so giving another creature the same ability would not only be redundant bout would decrease the value of the already existing creatures(one of them is a nymph, so ye it's a big deal).
Having a PA'ing creature would be too powerful and decrease the value of protect artifact itself.