I enjoyed this one. A simple story and one that's been done before, yes. But then, I like it when Discovery stops trying to be so damn convoluted that it vanishes up it's own arse, so I'm alright with that. The trick is to do a simple story with enough of your own flair and character work that it's enjoyable, and I think they did that.
I'm torn on Georgiou. I wish they'd left her behind because I hate the hammy cartoon character, but they didn't. So they can either use her to do nasty stuff while keeping our heroes' hands clean, or do a Road to Damascus story where she turns to the Federation values in a super cheese fest. Neither option is great, exactly, but at least the first is less cringey.
Stamets/Culber/Reno stuff was very funny, without seeming over the top, and I believed them as a crew on a starship working to fix a problem. Their story is pretty boring on paper, tech the tech to fix the ship, but the character stuff made it engaging. I laughed out loud at the bit with Gene, and that hasn't happened in Trek for some time.
I didn't really get the Detmer stuff, she just seemed to wander around with a concussion all episode, but I'm assuming that will pay off in the future.
V'draysh used as slang for Starfleet/Federation, specifically calls Saru a V'draysh Captain which strongly indicates to me they aren't some separate "bad Starfleet".
The planet visuals were great, the idea of a world built on impossibilities through technology is both nicely futuristic and yet quite TOS like (think the Cloud Miners).
Tilly continues to be an asset to this show. She fulfills many roles: audience surrogate, emotional heart, comic relief. Here she allowed us to see Saru's leadership style and feel the fear of the unknown that they must all have faced (although perhaps they hung a lantern on this a bit too starkly).