Spoiler So it turns out Tilly's arc is her being written out so Adira can take over as the ships science person.
That is not what is happening. Mary Wiseman isn't leaving the series and has stated in an interview that Tilly will return later in the season
I don't mind the actress at all, but I really hope the Academy series is not set in during the future DISCO period. I'd much prefer an Academy series during the early Starfleet times (maybe even starting out with UESPA before becoming Startfleet, Young Pike and Co).
Honestly having played the Starfleet Academy 1990s PC game from beginning to end, I personally think that's been explored all the way (yes I know most viewers don't play or even have heard of the games) and find the 32nd century setting a better place for creative freedom in an Academy show.
The only Academy show I'm really interested is one starring Data. (Spock would work too, but it would mean yet another actor for the character.) I suppose Julian might work for similar reasons and there would be an added layer of inherent suspense. *Actually, now that I think on it, Julian might be the best option. Plus, it's a leading role for a young Middle Eastern actor.
I think she only said Tilly's gonna be back, but not specifically back this season or even on this show. I'm sure she's gonna be in the academy show that was kind of confirmed on Sep 8.
According to the excerpts collected on Trekmovie, she actually confirmed to various outlets she's coming back in this season which is about everything CBS has allowed her to say... however, she apparently let slip to TV Insider that she will have a slightly different hairstyle and will be wearing a different outfit which kind of makes me worried that it's not an Academy uniform but rather a Mirror Universe captain's one.
But its not clear if as a regular or guest. If not im also not finally convinced she is moving to a new Academy show. She could move to Voyager along with Michael or Saru as Captain in a new Series !
What I'm most concerned about the possible Academy series is that we haven't quite received a confirmation on that, and Section 31 already establishes a bad precedent with something being floated for years as definitely coming or still being worked upon without anything substantial. And unlike Michelle Yeoh who does several high-profile movies every year, Mary Wiseman has been quite open about her difficulties getting other roles since COVID started; she doesn't quite have the luxury of waiting for years to see whether her vehicle is greenlit or not. So unless we're getting a confirmation on Academy, a Captain Saru Voyager series or her continued presence in Discovery in any capacity sometime in 2022, I don't think she's going to stay with CBS for long and we might actually see her signing on for something that would conflict with a possible Star Trek schedule. The rent doesn't pay itself, after all.
Tilly is irreplaceable. I do get that Adira already has taken on the role of Stamet's lab assistant and protege, however. Once he "adopted" Adira, it felt like Tilly was out in the cold as a character, so this is a nice departure. I thought Adira's character might be interesting, but lately is just kind of bland in a Chakotey kind of way. There's a use for bland characters as long as they aren't focused on too much. Even the character's detractors will probably admit, Tilly was never bland.
I can absolutely imagine her being on a cadet training ship threatened by the anomaly later in the season, but considering my nonexistent success with predicting how the seasons will go, I think we'll be lucky if seeing her later in the season amounts to more than a single scene in the last episode where she tells Burnham, Saru or Adira how much better she feels at the Academy, and that will be it, maybe with a montage of a few wordless hugs with the others.