You know... since up-thread it shows that MeTV has Voyage to the Bottom of the Sea following LIS, that show followed a similar pattern. The first season tried to follow the seriousness of the movie, but later seasons became the rubber monster of the week.
-PJ
Even ST:TOS was suffering by the third season (which the network didn’t want to give them, let alone a second). But it had more to do with a drastically curtailed budget that hampered what they could film. If they had been as well-funded as they were in the first season, one wonders how much better the quality of the eps would’ve been.