"The Enterprise crew encounters a phenomenon that forces them to face their innermost fears" is very well-trodden ground for this series, but this is probably one of the best examples. It coasts on a very well-executed horror story, and I thought it did a very good job in not tipping its hand as to which characters were real, and which were hallucinations.
Unfortunately, I don't think the stories of our two main characters were advanced much, if it all. La'An is still afraid there's a monster within her, and Spock still has issues with his duality, though this episode could mark the shift of his return to a more "Vulcan" way of being.
I thought the episode handled Kirk really well, though. From the moment they acknowledged that David was going to play a role in the series going forward, I had pretty high hopes - there are a lot of blanks to be filled in, since he was retconned into Kirk's backstory in 1982. Kirk's fears of being an absentee father, and of dying in some forgotten corner of space, feel very real, and I think they would feel real even if you didn't know how it's all going to turn out for him.
I thought the scene between Kirk and Uhura at the end was very...interesting. Not sure what to say about it, but it was interesting.
Yeah, I think I remember thinking the same thing.
I suppose that it would be sensible to keep someone with the shuttle Just In Case, though, and the Doc would certainly be more welcome on Kasq.