Except no matter how much you say it, he's not a 4. He doesn't need to be a 4 with DeAndre Jordan on the floor. You know the same DeAndre Jordan that is a monster rebounder with the second highest DRB% in the entire league? You think it's possible that Jordan may be taking 1-2 rebounds a game away from Luka? You cherry picked a stat that Luka has a low rebounding percentage for a PF and then fail to mentioned that he's playing alongside one of the best rebounders of the past decade.
The thing about these "advanced stats" is that a lot of them seem to exist for the sole purpose of internet guys to sort thru until they find one that fits they're argument on a particular player or team. If you sift thru enough of them you'll always find something to support your cause. 19.5, 6.5, and 4.5 are great numbers for a rookie with solid field goal percentages, there are no two ways about it they just are
I could give a damn about REB% and USG%. Luka is a very good basketball player with excellent numbers for a rookie. He's not Lebron but nobody ever said he was. He's probably going to win ROY and he's going to be a future all star. I don't need advanced metrics to tell me that, it's called the "eye test" and just in general knowing basketball. He's a winner that makes other players better (source: common sense)