It sucks to get your doors blown off by a KTM 450/525 EXC just because the guy has an extra gear.
I have a few friends in my group with some real nice KTMs, I ride them all the time. The 450's never out run my WR, my one buddy with the 525's got me beat by just a hair.. I think it says a lot that it takes a KTM with 60cc's more displacement and another gear to barely edge out the 5 valve Yamaha..
I mostly ride desert with some single track mixed in, even then I favor the 5 speed over a six speed, but if the WR ever gets a six speed I would hope that it's a closer ratio spread than the current 5 speed.