I believe to make the 'body to neck proportion' on the 5 strings similar to the 4 strings. Doesn't really bother me either way. I believe he made the body a bit thinner to offset for the slightly wider body at the 'tummy tuck' area.
I believe the NAMM LM's were still prototypes, so not sure if the 'final spec' will look like the trans wine pictured above.
I've had a lot of playing time on AC 5's with both wider and normal bodies (the bass Ken referred to above and the black RA5 now owned by Jonno), and I have to say I prefer the wider style - it just looks more proportionate. The wider one doesn't feel much different to play, so to me it's just an aesthetic thing. Not a deal breaker either way, though.


