My least favourite Season next to Season 17. While Season 20 has higher highs than Season 19, it's lows are unbelievably so low for Classic Who.
Arc of Infinity is beyond fucking dull. I thought Invasion of Time was bad enough in terms of Gallifrey's interpretation, but Arc of Infinity made it and it's citizens to be utterly boring and incompetent. These are not 'the most powerful God-like species in the universe' that stories like The War Games or Trial of a Timelord depicted them being. Omega is considerably inferior to his excellent portrayal in The Three Doctors, both in terms of character and especially in design. Barring scenes in Amsterdam, the atmosphere is so static and lifeless, the 5th Doctor is a complete idiot, and the one time he shouts at someone, it's at the one person that doesn't deserve it (poor Nyssa). Dreadful.
Snakedance in terms of a story and atmosphere is more cohesive than Kinda, although I kinda prefer the latter in terms of ambition and creativity, despite its rough edges. I like how the 5th Doctor is characterised, Janet Fielding is once again wonderful as a possessed Tegan, the story feels alive with some of the finest sets in Classic Who and the guest cast are deliciously entertaining, even with the campiness. Definitely one of three standouts in this Season.
Mawdryn Undead is a loved story by many people, but every time I try to watch it, I keep trying to ask myself if there's something missing in this story. Maybe it's because I don't find Mawdryn himself that effective of a villain, and I don't buy that Nyssa and Tegan are convinced that he is the Doctor. It's nice to see the Brigadier again, and by this point I enjoy what they were attempting to do with Turlough, but I find myself not going back to this story that much.
Terminus is quite possibly the most boring and 'cure for insomnia' story in Who History, and I'm including the expanded universe when I say that. Davison is completely pushed to the sidelines, never having any gravitas (it's no wonder that Davison wanted to leave by his 3rd Season), Tegan continues to be as unlikeable as ever, the sets are about as unmemorable as dry beige paint, the robots are laughably awful, the pace is at a slog with technobabble never being worse than in here, Turlough's arc does not advance in any way in this story, and the best 5th Doctor companion leaves here. Again, a nadir for the era.
Enlightenment is such a breath of fresh air for the Davison era and may be his finest TV story, barring Caves of Androzani. It amazes me that we finally get a 5th Doctor brimmed with complex, youthful, passionate, fiery emotions and I wished that we had this 5th Doctor throughout the entirety of his era. The sets and atmosphere are the best that Classic Who has ever had to offer, and it's criminal that Fiona Cumming has never been brought back to direct more Who stories, as she is the best director that Who has ever had. There's fantastic lore with the Eternals, and the Guardians are at their best in this, even more than The Key to Time arc. Utterly imaginative, daring, exciting, this is everything that I wanted from the Davison era.
How did we get from the excellence of Enlightenment to the utter incompetence of The King's Demons? Turlough is finally a member of the Tardis team, and he gets nothing to do, the characters are put in such a £5 pantomime manner that I can't even laugh at it to how awful it is, the action and tension are practically non-existent, The Master's plot is almost as nonsensical as his plan in Time-Flight, and it's just so boring.
The Five Doctors is certainly a great story, although I do prefer The Three Doctors in terms of multi-Doctor stories. Hurndell is an excellent successor to Hartnell, both in terms of mannerisms and performance, Troughton and Pertwee steal the whole show as usual, there's fascinating lore with Rassilon and Gallifrey that the show desperately needed after the awfulness of Arc of Infinity. Also, next to Survival, this may be Anthony Ainley's best story for the 80s Master. Best of all, all the references never hindered the story in any fashion and the story moves at a perfect pace. I really like this story.