I'd at least like my own stats reset. Right now I got pretty much everything unlocked because I shot a guy in the head and then died, suddently I was max level in pretty much everything, don't want that, I want to slowly fight my way there if anything. But it wouldn't be much fun if everyone else didn't have their stats reset and had max levels, you'd feel a bit.. left out.
My suggestion is to reset the stats for everyone, but allow people to choose one or two weapons and classes with a slightly higher level, for those who had actually gotten quite far in their leveling.
Or you could give current players a slightly higher level in all weapons/classes.