Great Potato
Preeminent
Kizaru sandbagging is very obvious, especially after the Nika dance in the flashback. Luffy still needs to fix his Stamina issues to be a solid Top Tier without Plot Armour
And if Kuma manages to do anything against Saturn, we will only need Doflamingo to be retconned once again when he reappears for all Warlords to have a potrayal above YC(not counting Buggy or Law who was a newbie warlord)
One thing that seems apparent is that the Government tends to recruit Warlords during their rise with the expectation that they'll continue growing while in their ranks. They tried to scout Ace early on in his career, took the gamble on Blackbeard seeing the momentum behind him, and were quick to snatch Hancock after her first bounty.
Sure enough, it didn't take long after leaving the Warlords for Law to become a 3B pirate who was half of a Yonko slaying duo, so if he remained in the program and it didn't get disbanded then he would have become one of their most valuable assets.