So Wiggins has a notably higher usage rate and plays four more minutes per game than Tatum... but Tatum tops him in every per-game stat, except PPG. And that shouldn't be a surprise, since you should score 5 more points per game if you're taking 3 more field goals and 4 more free throws per game.
Tatum needed to improve this year and didn't, don't get me wrong. His failure to maintain his surge at the end of last season, and his tendency to disappear in certain games, was a big reason the Celtics failed to meet expectations.
But he's better than Wiggins at that point in his career, and if you asked Minnesota to trade Wiggins for Tatum straight up today, they'd close the deal in record time and pop champagne. Wiggins has never have a positive box plus-minus or a positive VORP *at any point in his career.* Which is crazy to think about.