I'd like to suggest adding another component to this spell that could address some of the criticisms about the speed of tiering/UAC in general if not used to ambush from hiding.

I think this spell should add a bonus to automatically tiering up similiar to that given by the various punch/kick/grapple masteries. The bonus could track directly with that of the UAF bonus currently given by the spell (seed 1 Mental Lore, Transformation). I'd suggest starting it at a +10% floor which with enough lore can get up to +23% at 91 ranks of ML,T (same as the UAF bonus).