I wouldn't look for any big changes for the KDX. Look at it like this- is there any other bike which fits the same price range and features? Granted, the KDX is not a wild tiger compared to some other brand competition bikes, but the other bikes are more expensive, hyperactive, etc. The KDX fills a definite market niche.
The bottom line is that the KDX is good at what it is good at, which is a perky trail bike which can be improved with some mods, and Kawasaki sells a lot of them. If the bike continues to sell well, it'll probably remain unchanged.