To me what makes characters interesting are there arcs, not just how “fun” they are. TFA and TLJ accomplished this. TROS had cool character ‘moments,’ but it’s just about impossible to track any of the characters stories scene to scene. It’s a mess, which really sucks as a conclusion to their stories (especially when many of them undermine the lessons of the previous films).
I think that this is a result of TLJ. The second act of a trilogy is when most of your character’s development should occur, and Rian wasted it with the already-infamously bad Canto Bight subplot.