I recently changed from a KTM 640ADV to a WR250R. The only thing I miss about the 640 is the giggles when accelerating (and the kewl factor). Other than that the 250 is a much better bike for my adventures.
Maybe I'm gettin old, but I sure enjoy easy mounting/dismounting, being able to quickly put my foot down to keep from tipping over, having less weight to throw around in tight corners, and being able to easily pick up the bike.
The main advantage of the WR250R over a 200 class bike is cruise speed. It goes 60mph all day long with trail gearing. The main disadvantage of the WR250r is it's still too heavy to be a real good trail bike. If I was much shorter than my 6'1" it would be too tall too.