The thing is, nobody wanted to find out whodunnit. Not the heroes, as they feared Scotty dunnit. Not the beast, as it feasted on the fear of ambiguity and suspicion. Not the locals, who feared one of them dunnit, or, worse still, Scotty dunnit and walking away Scotty free due to being Starfleet.
And not the audience, which wasn't allowed to think Scotty dunnit and had nothing invested beyond that...
Stretching out detective fiction or courtroom drama when the issue of guilt isn't allowed to be dramatically interesting is gonna backfire. It only ever works if a hero comes under suspicion in the very cliffhanger bit, with the first part somehow keeping up our interest until then.
Sure, there was more story to "Wolf", and to "Court Martial", than was shown. But it was backstory. Would we really have wanted our extra 45 minutes of Star Trek to be another clip show like "The Menagerie", only now with "fresh" clips of bygone things?
Timo Saloniemi