I don't find what you say that shocking or heretical.
You are right...there were a a handful of episodes each season...yes Peter was a hard worker, a perfectionist..but the schedule he had was no where near the regular schedule of a tv show. And as far as James Garner and the Rockford Files goes...terrific show...I have only recently become a fan....great show...and wasn't he plagued with back problems?
I also love Magnum...some great chemistry between the regulars...and terrific writing.
It sure was lucky for Columbo that the murderer said "t'isn't," instead of catching himself and saying "If you say so" or something.
But we do have the surprise of Robert Vaughn getting killed and the "ah-ha" factor of the stencil message being revealed. ("He was going to marry the kid!")
The first time I saw LSTTC, its eccentricities drove me nuts, but now I have fun with it.
This is the only one of the original 45 I actually hate. The reasons have been discussed by others above. In a nutshell, though, it's just too quirky/eccentric for its own good. The finale is weak, and the whole episode feels like some snobby art-house film.