Tatum could significantly improve his game by simply protecting the ball better on drives.
He reminds me a little of a young Patrice Bergeron [how is that for a cross sport comp?]. As a teenaged rookie, Bergeron obviously lacked physical maturity - wasn't as fast or strong as he would be even 2 years later - but he could contribute because he seemed to have an innate understanding of the game.
Tatum is sort of like a more skilled version of that. As good as he was today, he'd be significantly better if he could simply protect the ball better on drives. He played 13 first half minutes and had 4 turnovers, at least 3 on drives where he just couldn't hang on to the ball - a common problem for him.
At the same time, it seems like he's adding new skills he can use on a weekly basis. He didn't shoot many floaters this season, but he had a beautiful one tonight. He's got the patience now to up fake around the hoop and let the defender leap out of way before putting in an easy layup (he and Al each scored a critical basket down the stretch that way tonight).
I'm starting to think the sky is the limit for him. He made some key defensive plays tonight, he's shown some abilty to create for teammates that he can surely build on, and he just looks like the sort of guy who can set his mind to developing some new skill and just do it.
People talk about flaws in his game, but the amazing thing about him right now is not that his game is perfect - it is how productive he is, anyway, despite the flaws, at age 20 in his first season. And it is that he has stepped up his game in the playoffs.