IIRC the reason behind the 2+3 crown headstock is that the B string on the tuner peg can get in the way of the E string in the 3+2 configuration.
[Edit:]More likely the E string getting in the way of the A string, but I digress.[/edit]
Not sure if it was to do with the interim Goto tuners that had the different ears and a wider peg.
(Message edited by adriaan on November 19, 2009)