http://www.bbc.co.uk/news/science-environment-13906169

Start debating.

Can't happen. By which I mean I won't let it, lest those days in 8th grade memorizing hundreds of digits of it to win a competition seem even less productive.

Though the value of pi arises from the circumference/area of a circle in relation to its radius, and that using tau may make that particular aspect a little more clean, I hardly think overriding such an ancient system to make a couple of equations easier is worth it. Maybe it does make life that much easier in more advanced forms of mathematics, but (practically speaking) almost nobody will encounter that. Perhaps they could instate the Tau as a neat little convention for those purposes?