I saw him during his senior year in HS when he played the Hoophall Classic. It was clear to me then that he was head and shoulders above the competition (and this is playing against a select bunch of top recruits, including his future teammate Ivan Rabb). At the time, he was primarily using his athleticism and getting to the basket at will. He could finish and draw contact at a rate that reminded me of other great NBA slashers (e.g., Wade; Gerald Wallace; Corey Maggette).
At Cal, he continued to show promise as a slasher-type scorer; he could get to the basket and finish using his athleticism, strength, and length. He also spent time playing some small-ball 4, which I think benefited his poor handle and shooting a bit. His versatility in college was impressive, as he spent time at three positions and could defend each relatively well.
I was thrilled when we drafted him because, as others have mentioned, he has the athletic tools to be a terrific player. I think he has a similar physical profile to Jimmy Butler, but with even more athleticism. We were able to see glimpses of his excellence last year, including a pretty polished mid post-game, an ability to get to the rim and finish, and score in transition. I think he even exceeded some expectations with his jumper a bit. I was surprised by how well he adapted to the NBA game, although he's far from a star at this point.
The criticisms are real, though. He has a poor handle, gets ahead of himself, and is spotty on defense. I think the best way to describe his game is "raw", for both good and bad. But with that said, I think that what I initially liked about his game still stands and gives me reason to believe that he could turn out to be a solid, if not great, player. Jaylen still holds the physical profile, athleticism, and some of the skills that he's always had, and he's even brushed up on some of his flaws as well. He has the foundation of a great player, so it's up to him to figure out how to make it work at this level.