Season 1 still seemed to be grounded in its hard-boiled roots by having Thomas Magnum as being a lot more gritty, cocky and arrogant. Later he becomes more like a bum and arguably duller. And the main characters are more like man-children. Even the episode titles changed.

I've watched through the first four seasons so far, and I was thinking mostly the same thing. Maybe is just a personal preference of how one likes their "crime drama" series, but, while I like a little comic relief in a serious crime story, the silly-type shows (which were somewhat fewer and far between in earlier seasons) begin to dominate, especially in the latter half of season 4.

For instance, the closer of season 4 ("I Witness") was the Rashomon theme, which had been covered earlier that 1983-84 season by...Diff'rent Strokes - to similar effect.

I guess, though, they were just giving the people what they wanted. The cast was superb, whether the material was serious or silly.

And I think, again, in tune with the times and the evolving nature of TV series, developed the personal stories and inter-relationships between the characters more - and in a way, involving (and hooking in) the viewer more. I'm sure it wasn't the first to do this, but kind of a forerunner I would say.

But yeah, I would agree for sure with your assessment.

In an earlier S4 episode, "Operation Silent Night" there was a point where T.C. stated "What'chu talkin' about, Higgins?"

Perhaps an inside joke that MPI was covering a DS episode later in the season?