Usually big time players try and shoot stylishly, they try and look cool when they shoot so they try and jump high, or kick their legs, or emulate players before them. In Evans' case, VC and LBJ. It usually has a negative effect.
You can't teach shooting. You can try and correct little tendencies, but you can't fix a player's shot after he's been using it for years. I've gone to basketball camps and worked on my shot and good habits while I was young so I'd honestly say I'm a good critic on "shots". He won't be much more than an okay shooter. He wastes motion with the leg kick and with his ear level shot. You won't see him shooting at a high percentage with consistency