It's really tough to compare DD to any past or present NBA player before. But watching him this year, i see a lot Latrell Sprewell.
Good mid range game, athletic, slasher, not a great 3pt shooter but is more than capable of hitting one if he's left wide open.
Sprewell i think is little bit better driving the ball/finishing but i think DeMar is a little bit more athletic.
Sprewell by the way was a heck of player in his prime when he was with the Warriors and Knicks. Multiple All-Star apperances, All NBA First team. Led the Knicks to an NBA Finals back in 1999.