I think I have come around on Sengun in the 7-10 range. I think you can argue that his size is marginally off from a typical C, and he hasn't shown range to shoot it, but I think you cannot ignore the production. The Turkish League may not entirely be the best in Europe, but it did have Euroleague champion Efes Andalou. Here is how Sengun did against the higher level talents:
As someone mentioned in the tweets, Jan Vesely and Bryan Dunston were matched up against him and those are two of the best defenders in Europe. Neither are the elite size he will face in the NBA, but those numbers are really good for a young player.
Beyond numbers, Sengun on film is physical in every way. He may not be a bouncy athlete like Khem Birch was for Toronto, but he honestly does challenge everything at the rim, goes hard for contested rebounds and tries to dunk on guys.
This past year Isaiah Stewart, the supposed throwback big was great in his role with Detroit, providing shotblocking, screening and some scoring upside (7 pt/6 reb /1.3 block). Sengun should be better because he has a similar motor and physicality but has a broader package of scoring skills.
What will be interesting is the Olympic qualifiers. I believe Sengun will play for Turkey and that NT is one that could knock off Canada but they won't have NBA guys like Kanter or Osman. Either way we will get our best look at Segun during that tournament. Birch might even get matched with him.