Dwight's always lacked offensive skill, and adding additional 'skills' will help, but with limited potential. His main problem is he has no sense of touch on his shot. He can't judge distance well. Watch him shoot anything around the rim that's not a dunk. He throws the ball AT the basket instead of up and INTO the basket. It's why anything he throws at the backboard is cringe worthy unless he hits it in exactly the right spot. If he doesn't, it's going to bounce 12 feet off the rim. He's learned touch on his free throws in practice through lots of repetition, but the fact that he can't reliably do it in games shows he doesn't have it naturally, because he reverts to chucking it up in the air with no sense of how hard/far he's throwing it.
Yes you can continue to develop and add skills as you get older, but I don't see Dwight being one of those guys. He just doesn't have the work ethic. Neither did Shaq. Karl Malone went from bad free throw shooter to great free throw shooter, but these two never could.