Best comparisons are McGrady Pierce and Durant.
actually, his offense reminds me a bit of a combo between Gervin and Bernard King. It's still early but he could be the answer to our awful scoring droughts if he comes close to that level
Who?
How about some modern player comparisons 
should go back and watch of those guys if you can -- the days when there were real NBA games. can't stand today's NBA so I wouldn't sully Tatum's potential with latter-day player comparison's.
Ok...
What do you think of Tatum to Clyde/Dr J comparisons?
he seems to be more of a shooter than they were. they were more drivers than shooters. King and Gervin were more of a mix although Tatum's finger roll made me think Gervin immediately
Clyde the Glide Dr J are actually more similar to Josh Jackson than Tatum.
Tatum's body is shape is virtually identical to Pippen. Both Tatum and Pippen are extremely smooth players. Watching the way Tatum moves with the ball, the smooth deliberate motion he takes to get to his shot. Yes his step back gam winner was reminiscent of Pierce, but Pippen had a step back shot too. Look at the moves when Tatum slides to the rim, and I don't say drive because some times it looks like he just glides to the rim, that's Pippen. Pippen had an absolutely sweet midrange game with smooth pull ups and jab steps just like Tatum.