Good copper shows, in my opinion.
Lewis has it, Foyle, Midsommer, Frost, Vera......some others.
Good copper shows are about the crime, the mystery.
The protagonists and/or their wives, cousins, uncles, and nuts or dogs do not get kidnapped by alien terrorists or are to any great extent involved at all in the actual deed(s).
They do not have affairs with each other, othe s in the office, or the respective wives cousins uncles aunts or dogs of the protagonists.
To the extent you know of there personal lives, it is tangential to the story, and is presented so that you know more about what makes the protagonists tick.
When copper shows do resort to wives, cousins, aunts uncles, or dogs, it's because they've run out of good ideas, I think.
I still like copper shows in general, but the ones I like best are not old fashioned whodunnits.