Tsuru

⚠️*DISCLAIMER*⚠️

I have NOT read the Manga so I don't know as much.

Tashigi, Koby and Helmeppo as the admirals. Tashigi and Coby probably makes sense but Helemppo (eh). The current admirals and vice admirals will be old. Sakazuki, Borasalino, Ryokugyu and Fujitora will most definitely be defeated in the final war. The current vice and rear admirals have no chance in the plot of improving. Tsuru is to old. Garp will never say yes. Gion and Tokikake/the admiral candidates will have their moments but will be replaced by Koby Helmeppo and Tashigi. Smoker has a straight losing streak and is WEAK AS FUCK. Hina is weaker than smoker and is just a little irrelevant. Full-boy or what ever his name is and Jango are just jack offs used for jokes. Bastille weak, Maynard weak, Momonga weak, blablablablablablabla. But the problem is the Fleet admiral. It will maybe be Garp because it doesn't seem like they care or report straight towards the Celestial dragons. They report to the Gorosei/more civilized celestial dragons. But if Koby is then I don't know.

I think somewhat similar to Shakky and Rayleigh whenever Tsuru actually retires Sengoku and Tsuru are going to get together.

They entered the marines at the same time 56 years ago along with Garp. [Smoker and Hina seemed to have been trained in the same class, and we see what that did for their interactions. I think there are hints of something there.] Furthermore, Sengoku out of all the marines chose to come with Tsuru to Dressrosa. [Of course he was coming to Dressrosa regardless being that it was related to the Rosinante matter. But, as opposed to with the other marines Sengoku arrived with Tsuru.]

There is of course their interactions where Sengoku mildly annoys Tsuru in a somewhat endearing manner.

Also, according the wiki when Sengoku was an admiral he ordered Tsuru to stop the Doflamingo prates, he was overseeing her. And according to her Vivre Card she served as Sengoku's personal assistant and aide [presumably when he was a Fleet Admiral I'm guessing].

Lastly, they are pretty similar, both of them are very much the strategic side of battle, and level-headed people. They also seem to emphasize duty as we saw with during Ace's execution. I think they suit each other well.