I've seen him dribble his way to the basket many times. He can also make space for his jumper. If you can't recognize what he is doing then we don't have much to discuss about. He is young player and he could definitely add some more muscle to his frame. His feet is excellent for player his size. He can play above the rim if needed, but that wasn't his role in Arizona. He has been our better defenders in european championships against older guys. Think with all those players you mentioned is that they have grown to the players who they are today.
Trier is very hard player to play with. He is elite ball-handler who doesn't know how to pass. Markkanen had much better looks before Trier came in.
You don't seem to understand roles are outlined for each position. You sound clueless when you say a PF's role wasn't to rebound.. That's one of the dumbest things I've ever heard.
Also, he doesn't create off the bounce, he can drive after a catch and an overcommit. Big difference... He can't create his own shot, he's a pick and pop/ catch and shoot scorer.
That's great that he was a good defender in Euro league, but the NBA is a different animal...
If you understand basketball and have payed attention to which skills translate, you'd have a better understanding of his limited ceiling. 7 footers with varying qualities are selected every year in hopes they can develop a second or a 3rd NBA skill. Markkanen is just unique in which skill he already possesses. Shooting and a lot of offensive tools can be developed - length, athleticism and IQ are natural and can't be taught. That's where the red flags come.
If you'd been paying attention beyond a year ago, you'd be aware of the hundreds of big guys who've come through with the same story... Out of the NBA in 3 years.... I'm not suggesting that's him, but realistically his upside is a good rotation player, not a superstar as you've suggested.