Which is not to say they're boring. I really grew to care about the characters, & when bad thing(s) happened to one (or more)* of the regulars, it really moved me.
The islands play a big part in the series; as at least one other reviewer observed, the land & sea are pretty much main characters as well as the people. Beautifully filmed in a gorgeous (if minimalist) land, the scenery makes me want to go there to get in touch with my own Scottish roots.
Lovely series; I hope the Beeb has more sense than most of US TV decision-makers & keeps it up (this show wouldn't have lasted a full season on a US channel...too intelligent & classy).
It occurred to me mid-way thru the second run thru that part of what I like about the characters is that the actors look like real people, rather than the plastic Barbie/Ken people that we get on US TV shows; older characters may have belly bulges or wrinkles. Most look as if they've never been near a Botox needle. There's very attractive people, and some very unattractive people. Realistic people. What a concept!
Though, one silly nit-pick: why does the GP who does the forensic work for the Shetland police always shake down her electronic thermometer?
*trying not to intro any spoilers