[Some spoilers about a character]
As Discovery matured it got into a rhythm of its own kind of wacky space-opera versus (or complimentary with) more The Next Generation style episodes. I’m sure there are examples of each from various directors but the first category I associate with Olatunde Osunsanmi and who better to represent the second than Jonathan “Will Riker” Frakes.
True to form we get an episode that is so TNG that we get the return of the Trill and a new Wesley Crusher-like character. Yet this is Discovery, so this is still TNG but updated and with its own spin.
The twist is that the planet that gets the TNG treatment (where a whole planet of people gets boiled down to one character who basically makes planet wide policy on the spot having been shown the error of their ways by the stern wisdom of the charismatic Starfleet captain) is Earth. Yes, the episode has all the flaws of the standard Picard solution of getting two antagonistic space-groups to realise what they have in common and work together rather than fighting a war. It’s too quick, too simplistic and utterly unlike any actual real world dispute. However, making the snooty up-itself planet Earth…that is actually quite a neat twist. How intentional that was, I don’t know but it adds a spin to a corny scenario that has a nice subversive quality to it and acts as a mild critique of all those “why don’t you two just put aside your differences and get along” episodes from the original series onward.
Meanwhile, we get another new character: Adira, a hyper-intelligent teenager from future Earth who is part of the Earth defence boarding party. Played by Blu del Barrio they aren’t nearly as annoying as Wesley Crusher and their big secret [spoiler] is that they are actually a human with a Trill-symbiont . del Barrio is non-binary and that is a neat casting choice for a class of Trek characters that have had an interesting play on questions of identity.
Still…I can’t help feeling that Discovery already has more characters than it is properly utilising. The under-used bridge crew do get some collective moments (greeting Michael, visiting a great big tree) but aside from a brief hesitation, we don’t get an update about whatever is going on with Detmer.
Even so, the episode uses the emotions of the crew well. Even though Michael has only been separated from them by two episodes, I found the initial reunion quite moving. I’m also really glad that Saru is now wholly and unambiguously the captain of the Discovery. It’s an ill fated role but it is an outcome that retrospectively makes the previous seasons better. The Discovery was a dysfunctional ship with a dysfunctional crew many of whom were individually capable. Events have changed them and the ship and Saru’s captaincy emphasises that as a story arc, even if some of that arc was unintentional.
 I assume that will engender some arguments about how the whole Trill thing was supposed to work but in a nod to continuity, Saru had to learn about the Trill’s symbiotic thing courtesy of the sphere data. Riker/Frakes of course was briefly a host for a Trill-symbiont in the TNG episode where the species was introduced.