[@Heavy Snark]: Okay, where do I start...
Well, how about the elephant in the room: that's a wolf. You'd just be playing a wolf. A wolf that wholly understands human speech, yes, but a wolf nonetheless. No speaking, no active interaction, no nothing. Already, that's a big problem, as I am fairly certain that the other people with Masters are not particularly inclined to simply having a sapient wolf for a Servant (as opposed to, like, Lobo). I could be wrong (and people should be correcting me if I am), but given who does and does not have a Servant already, this is my current opinion on the matter.
That aside, we already have precedent for a character using cursed pelts to transform with Atalanta, who can more or less swap to Calydonian Boar form and back with that NP active. Being locked to wolf just seems sort of needlessly restrictive.

Ergo, rejected.