Warning: SPOILERS for Star Trek: Discovery Season 4, Episode 9 - "Rubicon"
The Ni'Var, home to the Vulcans, Romulans, and the Qowat Milat warrior nuns. The Vulcan President recently negotiated Ni'Var's return to the United Federation of Planets after a century apart.
The neat paradigm on the bridge of the Starship Enterprise in Star Trek: The Original Series became harder to justify as the films continued. In TOS, Kirk was Captain, Spock was First Officer and Science Officer, while the rest of the crew had defined roles and held rank accordingly. By the later Star Trek movies, everyone in the cast was promoted and the Enterprise's command structure made less sense. Kirk was formerly an iral who was demoted back to Captain in Star Trek IV: The Voyage Home, but Spock also held the rank of Captain. Yet the Enterprise continued with two Captains in Star Trek V: The Final Frontier and Star Trek VI: The Undiscovered Country. To justify it, the Vulcan simply stated he had no wish to command his own starship and he yielded the Captain's chair to his best friend, Jim Kirk, whose best destiny is commanding the Enterprise.
Saru's love story with T'Rina has been brewing since they met in Star Trek: Discovery season 3 but by season 4, the Kelpien/Vulcan romance distracts from how the USS Discovery now has the same problem as Kirk's Enterprise in the Star Trek movies. Saru still holds the rank of Captain and he's a capable and experienced commander who should lead his own starship. Yet Saru has taken the lesser role of serving as Captain Burnham's First Officer. While Michael and Saru have a friendship that literally goes back 900 years, they don't have the bond of brotherhood Kirk and Spock had. There was more logic to Captain Spock choosing to be second to Captain Kirk but it doesn't make quite as much sense for Saru to yield as Michael's Number One, especially considering how much the Kelpien wanted command of Discovery in seasons 2 and 3.
Of course, the real-world reason for Saru choosing to become Captain Burnham's First Officer is the same as why Spock still served under Kirk in the Star Trek movies: Like Spock, Saru is a main character on Star Trek: Discovery and he has to remain as part of the bridge crew. Logically, Saru should have made the same choice as Mr. Sulu (George Takei) and become Captain of his own starship, as Sulu did the USS Excelsior in Star Trek VI. Unfortunately, Saru accepting command of another ship would take him away from the main action of the series, similar to Lt. Sylvia Tilly (Mary Wiseman), who hasn't been seen since she left Discovery to teach at Starfleet Academy. Mr. Saru already previously vacated Discovery's Captain's chair to spend time on his homeworld of Kaminar with his ward, Su'Kal (Bill Irwin).
The best options for Captain Saru in-universe would remove him from the bridge of the USS Discovery now that Michael Burnham has achieved her Captaincy. Star Trek: Discovery has placed Saru in an unfortunate Captain-in-waiting role while he performs First Officer duties that are actually beneath him at this point in his career. As entertaining as the slow-burn Saru and T'Rina romance is, it's almost like a sleight-of-hand to obfuscate how directionless Mr. Saru's Starfleet career has become otherwise. As fun as it will be to see Saru and T'Rina pursue a relationship, it also raises the question of what kind of future Saru and T'Rina could have together. It seems every avenue for the couple, if they became serious, would almost certainly continue to deny Star Trek: Discovery of Captain Saru, a rank he worked hard to earn.
Star Trek: Discovery season 4 streams Thursdays on Paramount+.