Sure. The mancrush on JV is based on his basic tools, level of competition/experience and the improvement you can see in his game and body over several years worth of youtube. There are now 32 pages of discussion here that contain better analysis than I can provide:
https://forums.realgm.com/boards/viewtopic.php?f=3&t=1090163
The short version is that JV possesses an elite combination of length, hands/touch, athleticism and instincts, with an aggressiveness around the basket on both ends that defies his European heritage. His second jump is super quick and he has a knack for converting in traffic. Jonas is a force around the rim. Plus, you can't foul him as he shoots FTs @ 90%. JV does not have a polished post game but has shown some new moves over the season. By all accounts he has phenomenal intangibles and puts the work in.
Statistics back him up. Jonas scored almost 8 ppg which doesn't look that impressive at first. However, the fact that he had very little post game, limited minutes, and the ball almost never was passed to him makes that number look a lot better, particularly paired with his 70% shooting. He led or almost led (depending on how you read the numbers) the Euroleague in boards/min. This is as a rookie 18 year old in the most competitive league outside the NBA. Rebounding is a skill that translates very well, he's going to be effective in the NBA in this regard.
His athleticism is deceptive as he doesn't usually come off the floor very high. But that doesn't mean he can't.
https://www.youtube.com/watch?v=SYy6xvSrIHM&feature=player_embedded
That's nasty. Probably the biggest dig on JV I see is that people don't think he is enough of an athlete. Well there you go.
*This is only the short version compared to the 32 pages of yammering going on in realgm.