Well if you start using it now, it might mean that once B16 and that model is enforced, you'll be more used to it than everyone else?
I don't see what the big deal is, it just means you no longer have to shoot through people's foreheads since the crouching stance is more accurately reflected to that of its hitbox.
3/4 of eR33t seems to be using the B15 with little or no complaints, I'm sure everyone else can too.