The problem, however, apparently isn't that the main characters aren't getting more development... in fact, a lot of criticism is centered on the focus on the main characters being to the detriment of the supporting cast. I agree that Discovery seems far better in giving the main cast better defined character arcs in this season than the mainly plot-driven previous seasons, but most people seem to complain about minor supporting characters not being fleshed out. When Tilly was made first officer in Season 3, a lot of its criticism wasn't about how she was unsuited for the role but rather that the focus on her apparently robbed Nilsson of an opportunity to "be developed" and have her day in the limelight in the captain's chair. None of the arguments I've read online actually explain why the show would need to develop these minor characters, especially Nilsson who is as close to a blank slate as one could get, and especially at the expense of Tilly who was a main character in dire need of a character arc (even one as controversial as it ended up being) after practically being reduced to a single-line-per-episode Mary-Does-Cringe-Comedy gimmick in Season 2.
At this point one might start wondering if the small bits they've seen of Owo, Detmer, Linus et al are really so intriguing that they actually want the show to develop them even at the expense of the main characters not getting actual character development, or if they simply dislike the main characters who are currently being focused on (or at least their storylines), and want to see stories focusing on literally anybody else. If Owo and Detmer not being developed is a problem, then I think one also has to explain why not learning more about Michael Eddington or Ensign Whatshername who is periodically seen sitting at the helm next to Data is not a problem.