I haven't rewatched it in awhile, but I feel as though one of the things that bugged me about the final episodes of S3 was that even though there were two separate threats at the time (the Emerald Chain capturing Discovery and the folks stuck on the holoship on the dilithium planet), Burnham to some degree comes across as a key player in addressing both problems. She's interacting with Su'kal more than Saru is until Discovery is imperiled, at which point she switches story arcs and gets onto Discovery to play a key part in retaking the ship.
I'm not sure I'm being fair here...like I said, I haven't rewatched it in awhile...but I would have liked to see more of Tilly as Captain (as vaguely ludicrous as that was in principle, I enjoy Tilly as a character more than Burnham) and more of Saru himself with Su'kal (in the end there's a decent amount of that...once Burnham is gone).
This is perhaps symptomatic of a larger issue that led to me often feeling like DISCO was "The Michael Burnham Hour", where TPTB didn't seem to trust any character other than Burnham to be able to carry a significant storyline...or were perhaps under orders not to.