I think this belongs in Gen Media, not Science Fiction.
But Dietrich was an alien...

Dietrich was awesome. He was smart and cool and funny. And I admired his conscience too. I still remember the episode where he had to shoot someone in the line of duty and felt really guilty about it and considered resigning because of it, because he thought he hated violence too much to be qualified to carry a gun. That was one of those times when I came up with a line I would've written into the script given a chance. I wanted Barney to tell Dietrich that there was nobody he'd trust more with a gun than the person who least wanted to use it.
That is a good line.

That being said, and I admit my memory of that episode might be fuzzy after so many years, but wasn't the real point of that episode as much about Dietrich's status as an occupational dilettante as about his conscience? IIRC, there was an exchange between him and Barney about how Dietrich had a tendency to "get into the wrong field," get challenged by something and then quit. While you quote doesn't necessarily contradict that, it might have distracted from the point the writers seemed to be making, which about Dietrich coming to terms with being a career cop and that, in fact, he was suited for the job.
The only guy on any modern cop show that looked like he could perhaps fit in with Barney Miller would be Lenny Briscoe. He seemed to have a similar sense of humour.![]()
Dutch and Wyms from the Shield would have been quite at home (and probably much happier) transferring into the 12th Precinct.