While I have no problem with the sign itsself, to me it seems like we're trying to create a handsign just so we can 'be like the cool kids'.
It feels forced. Maybe even a little desperate.
If it takes, maybe I'll feel differently ten years down the line when I'm driving through Montana and I see a BYU bumper sticker and we flash the Y. I have to admit it would be cool to have that connection.
But at the moment, I don't like the idea of trying to create it out of nothing just to copy other programs. It's like an NBA player trying to give himself a nickname.