I will say this on Vierling. Defensively he is very good in the corners and can hold his own in CF, he can play 1B and can stand at 3B (neither of which are primary positions but are nice on the bench). As for stats, he has a history of good plate discipline and that there is a reason everyone related to AAA got let go as well as the MLB hitting coach and it is because everything that touched those two withered and died. All of that combines to put the floor as 4th/5th OF type with good bench versatility.
However, in AA, AAA, and then the majors his exit velocity numbers stand out. Among players with at least 50 PAs in the majors his 91.5 mph is 43rd sitting in a group with Matt Olson, Joey Gallo, Bo Bichette, Kyle Tucker, and Freddie Freeman. Exit velocity isn't everything, and he suffers from much of the same problems as Alec Bohm (who is ahead of him at 36th at 92.0) where he needs to elevate the ball more to really tap into it. But it gives him ceiling, he is exactly the type of player that Kevin Long has gotten something out of in the past and there is a path here where he is Justin Turner at the plate and suddenly he is a very good everyday player. Not saying it will happen, but there isn't a path forward like that for Moniak or Haseley.
So he isn't the new hotness as much as he is a guy with some real underlying skills who has a clear path to being a major league contributor now with the tools where he could become an impact player (even if it is more of 80+ percentile outcome). For me he sits 9th in the system sitting firmly between the interesting upside guys at the top and the mess of young players who haven't played and the upper minors guys with real question marks.