I was sitting back watching the highlights on youtube, and this made shot by Barrett got me to sit up in my chair and go back/watch it in slow motion on .25 and pause step by step. I wanted to see why his shooting numbers have always been relatively poor and break down some of the issues I see in his mechanics.
For a team such as us that is starved for good shooters, we're still going to have spacing issues for the most part - this was less of an issue last night, but I think the problem will still rear its head in many future games until we shore up shooting completely (and that issue likely won't be fixed this year):
In the first image you can already see how far away and low his starting point is. It's well ahead out infront of his eyes instead of cocked closer/higher, that release point will make it hard to have an arc release because he's too far out infront of his head. It becomes more of a push shot rather than a naturally good/cocked high release. His toes also point away from the basket more to the right side while his upper body is pointing toward the basket (not a huge deal because he's still fairly square overall).

In the second image, the ball is practically touching his forehead in a horizontal line - it's way too close and way too low. When you cock back, the ball should be slightly higher than your head by this point. He's essentially blocking his own vision to the basket in both the first and second screenshots.

In the third image, while his body is completely vertical now - which is good, look at his left and right hands, they're almost touching at the top. When I shoot my left hand naturally drops down off the ball and it's almost completely guided by my right hand after release. His right hand should be dropped down below the elevation of his left hand, but they're touching at the apex.

This is pronounced in the last image where you can see his right hand is still completely up after release, and his left wrist is going completely west. His follow through should be toward the basket, and instead his wrist is pointing the complete opposite way to the left (again this isn't an image pixelation thing, I watched this shot at full speed several times and you see his wrist just jut out left).

His shooting form definitely seems fixable as he's fine vertically and fairly square, but I hope they notice some of these problems in his release and tell him to change his starting point as I can see him shooting a lot of line drive shots all season long unless it's addressed.
I watched him shoot a few practice shots as well the other day and saw him miss a couple and saw the same mechanical issues in that video from different angles.
(sorry about image sizes as the sites I used are resizing them!)