You did notice the seakings at mermaid island were like a 100 times bigger than the one Shanks scared off ._. infact, those were bigger than any sea king anybody was ever seen fighting so far(maybe except the goldfish at little garden)
of course but what I meant is that those were overpowered by these guys. so the bigger ones could put up a match but I'd say an admiral or a yonko could still take them. I mean look at oz doflamingo and moria screwed him. big size has downsides as well.
for example since they are so big they are easy targets for akainu. though they can always dive in and get away.
aokiji can froze the sea itself so he's got a pretty huge advantage over the sea kings.
kizaru's attack against trafalgar when he was taking luffy out of the marineford would destroy those giant sea kings.
and more but I'm talking about one sea king at a time. if there are more things would get messed up.
right after he lost his arm while saving luffy
