I watched this for the guest stars, although they're never given enough scope to show off. I like some light mysteries, but this series just doesn't grip me. Some people might be offended that the main detective is white, as if there were no local person who was smart enough to solve the crimes. The female Assistant Detective is also made to wear skimpy, unprofessional clothing, which could rankle if this were a more serious show. But there is almost nothing serious about Death in Paradise, so I don't expect many people get up in arms over it, myself included.
I expect lead actor Ben Miller left after two series because he was bored. Who could blame him?