After the 18th season met with such generally positive response from fans, the 19th was mostly mixed. John Nathan Turner felt he couldn't possibly compete with the legacy of Tom Baker, so he wanted someone as different as possible. Peter Davison was an instance of nepotism-- as they'd worked together before on ALL CREATURES GREAT AND SMALL. Nobody seemed to have any idea what the new Doctor would be like, and they deliberately scheduled his 1st story to be filmed 4th, to help give them time to figure him out. I'm not sure it worked, though.
As with LOGOPOLIS, CASTROVALVA starts out with multiple references to earlier stories (but all done so vaguely only longtime fans could pick up on it). The TARDIS heading for the "big bang" replays the climax of the 3rd William Hartnell story. As things go along, the writing, directing & acting all are sub-standard. I'm afraid that while Christopher Bidmead was a wonderful story editor (he burned himself out after only one season by working himself too hard), he's really only a 3rd-rate writer. It's taken me decades to come to this conclusion; I guess my sensibilities just keep getting sharper.
I rather liked seeing Davison in Tom Baker's black & gold vest. But when he ditched that for the "cricket" outfit... oy. Starting here, characters on this show no longer wore clothes-- they wore "costumes", or "uniforms". JNT may have claimed this was to make them more "recognizable" or "marketable", but really, it's just trimming the budget so he could spend the money elsewhere. (Before taking over from Graham Williams, that was one his his specialties!)
The tribute to M.C. Escher in the concept and visual design of "Castrovalva" was probably the highlight of the entire serial. Beyond that, everyone in it seems dense. Anthony Ainley-- I like to think-- MUST be a better actor than he's given a chance to be. Apart from the absurd costume and really bad haircut, he was apparently told to "over-act" in every scene where he's seen as The Master. (It took until "Survival" before we finally got to see what he could do if he "toned it down" the way he always wanted to.) Roger Delgado, he AIN'T.
Between Adric, Nyssa & Tegan, the TARDIS was over-loaded. JNT may have wanted to pay tribute to the original TARDIS crew, but back then, you had 2 brainy adults and a very strange teenager. Here, you have 2 brainy teenagers and a bossy loudmouth. Oh yeah, and a Doctor who was passive instead of seeming "experienced". It just didn't work. It's no wonder Davison is my LEAST-favorite of all The Doctors. I like him-- I just don't like his Doctor. He was put to much better use when he played Albert CAMPION for 2 seasons of that show a decade later.
Unfortunately, the worst Adric story is coming up next... but I guess I'll "have" to sit thru it again. I have every other one up to this point.