The bottom line with James is that he is not a scrapper. He lacks toughness. Additionally, he is black or white in his skillset. He does some things, such as shoot, really well. He is weak in other areas such as handling.
He is also not a particularly smart player. What I mean by that, is that some guys can adjust and adapt. For example, Kris can stay outside if you take away his inside game and vice versa. CJ somehow always seems to find his spots. With James, either his skills are working or not. There is no secondary dimension to his game. So maybe saying he is not smart is an improper statement as opposed to saying he is not multi-dimensional. However, truly good players will find something that works even when part of their game is taken away or simply are not effective in a given game. With James, it just never seems like he adapts, be that as it may from lack of a broad enough skillset or from an inability to mentally adjust to what is available.
Regardless, I think James will have his moments when he gets hot and the team needs exactly what he is capable of delivering.
The problem is that unless he becomes a reliable player instead of a hot & cold streaky player, that barring injury, he will remain on the fringe of the rotation and not be an integral part of that rotation.
Jimmy almost always will play the guys that he trusts.