I somewhat agree that Admirals are more interesting than Yonko's
But that is only because Oda didn't focus on admirals enough to make them fools like Yonko
You know damn well Admirals will suffer same treatment
Oda just writes them better, there’s no need for any caveats and waiting for them to (once again) take the spot light. Fujitora as a character grapples with the corruption of the world government and the place the marines have in shutting down threats like Doflamingo. He blinded himself over the evils he saw in the world. He’s got a strong sense of purpose in the world. Aokijis entire relationship with Robin in Water7/Ennis Lobby speaks to his values more than any season any Yonkou has gone through.
Kizaru, the more gag related admiral, still maintains a strong persona about him even when being undermined by Apoo.
Whereas the Yonko, their values and goals are either bathed in mystery or outright simplistic. It’s hard to take Kaido seriously as an antagonist when his overarching goal is world war for the sake of it.