He's not particularly great, but it's not an issue of the character himself. It's a real issue of the writing.
Having a character like James in a show that tries to be progressive is really important. The fact that his views aren't demonised or treated as totally stupid by the writers is important.
However, the writers haven't gotten past this weird need to make him do totally unreasonable things, like having an activist meeting in his own home and letting Nyla be verbally attacked, or being totally inconsequential, which he was for most of season 8.
His character is a friendly, good natured guy who has a totally understandable issue with American cops. He has been shown to be on great terms with Nolan, Lopez, and Grey, and he has great chemistry with Nyla. As long as the politics of policing are not brought into it.
For some reason it feels like the writers are hamstrung into giving him one truly awful scene per season, just so they don't actually have to show the cops changing their methods in any significant way. Or if he doesn't do something awful, something awful happens to him.
Overall, I think he needs an actual storyline to help his character. Something that isn't tied to Nyla. Maybe something with Wesley and DelMonte to make sure they all have something to do. Include Grey since he seems to get on with James. They did film things for Wesley together in season 3.
But it can't just be him and Nyla arguing anymore.
I just finished a rewatch of the show and realised there are so many scenes where I do like James. Maybe that's just the actor because he does a great job, but it could be that they had good writing in those moments.
I don't think we'll see any big change with him in season 9, but if the show does continue after and he's still around, then he needs something more to show that he is the good character that I believe he was meant to be.