I think what some don't understand is that a PG is a mindset. Just being short is not a PG. Yes there are skills associated with PG play like ballhandling and passing, but court awareness, actually wanting to find your teammate, taking joy in the assist, knowing how to set guys up to get good looks, that's PG play.
The reason Epps struggled, in my opinion, is because he had a scoring mindset. He didn't want to set anyone else up. He wanted to get to the rim. He wanted to take the shot. That is a recipe for a bad offense.
So when you look at someone like DGL, he strikes me more as a guy who wants to score than facilitate. I know nothing about that Chris Johnson, but that's the question you'd need to ask. You can be a scoring PG, but you have to have that mindset of setting up your teammates, facilitating the offense, using your drive to break down the defense and find the open man to be a real PG. That's why a PG is so important, they set everyone else up. Another guy looking to score with the ball leads to too much one on one crap.