And far less exposure than Kaido, Katakuri, Doflamingo, Lucci etc got, the list goes on and on. What does Kizaru specifically have to do with this lmao? You keep bringing him up, not me, no idea why you're so hyperfixated on him in this discussion, like sure, Kizaru's power was under utilized, maybe has a role to play in the future, who knows.
So a couple rounds of no diffing people in a few pages and then a two chapter fight that constantly switches between Vergo vs Law and other Straw Hats. That's a mere fraction of what actual main villains like those I mentioned above got. Nowhere near enough time to flesh out his powers.
Caesar the character got an arc largely centered around him, though Vergo arguably took that when he appeared. His power did not get the spotlight at all, and because of the way Oda wrote his character, as a weak coward, his power was never actually demonstrated as effectively as it could or should have been.