I understand why people didn't like it, but honestly I felt this was actually my favorite of the episodes so far this season. Having the holodeck at all I do think is a quite a large problem, and continues this show's weird disregard for canon, but once we move past that I thought it was fun. I think my issue with most of the wacky episodes of this show is that they actually happen to the characters. Spock turning into a human or Freaky Friday-ing with his fiance are events that I'm never really able to suspend my disbelief about. I was more at ease accepting the holodeck versions of characters rather than the mind wiped versions of them we got two episodes ago.
Seeing young Scotty as incredibly competent, but still having room to grow was a good choice, and feels like a natural evolution (or de-evolution) of his character. Paul Wesley's Shatner impression was quite amusing I'll admit. I've been pleased with his performance as Kirk in other episodes, so I'm happy to let him have a little fun with it. The intro for the fake-Trek show was actually pretty interesting, I could see why that would be annoying and pandering if it was the whole episode, but I'm surprised we didn't see more of it.
That being said, there's some big downsides. The holodeck's existence just shines another light on the fact that making a pre-TOS show is more of a mess than it's worth. The fact that it looked exactly like TNG's holodeck almost makes it worse. While I did like the concept of the show, I'll admit I couldn't follow the murder mystery at all. There were too many players, too many plots, and I really couldn't understand who was who. I pegged Spock as being a hologram immediately, so while I wasn't surprised at that reveal, I was surprised that he was the killer, which feels like would be a really terrible conclusion if I was actually in La'an's position, trying to solve a mystery. Finally, I really hate this La'an x Spock relationship. I think the Chapel x Spock one had way, way outstayed its welcome, and to immediately put him into another is frankly exhausting. Given how the others have gone, I seriously doubt this relationship will be meaningful or worthwhile, and I expect it to fizzle out unceremoneously in a few episodes. La'an already had this unrequited love with alt!Kirk, which I thought was a much more interesting concept, although I'm fine that's over too. Get Spock back into an awkward relationship with T'Pring if you must, but I'm really not looking forward to this.