I must admit I found some of the earlier Shetlands really boring, and unnecessarily complicated family history, so on a crime level it was quite tedious.
And half cooked suit pudding Perez was a real turn off. But the difference was that through the series they developed the central characters and their story line. And even though I was really sad I suspect Duncan's end was almost bound to happen.
But the writers or writer just dont seem to be bothered with Tosh and Ruth and I suspect it is because they are female characters. They just lurch from one cliche to another.
Can you imagine Sally Wainwright giving lead female characters such facile lines.
But I think any series that starts based on a sucessful book it always going to be better than the generic 9pm slot. But suspect even Strike if it was no longer based on books by JKR would not be as good.
If I could be bothered I might check who the different script writers have been but on one level this was quite slapdash and sort of relied on a convoluted plot. Although it is a Shetland tradition to have lots of red herrings. And characters just disappearing having been the focus to begin with.