I own a 2011 MIM P and a 2008. The older is slightly chunkier but it actually feels better to me; nut width is the very same. I find it very "in the middle", as I find jazz measures too thin, and Classic 50s (44mm) too much.
I think what makes MIM necks great comfort is the C shape. My Gibson's neck is 42mm but D shaped and it feels much bigger than what it is actually.