It does not really matter that much for either Kaido's or Luffy's fruits if they are meant with what the Gorosei are talking about, cause both abilities will end up being atleast in the top5 of body transforming abilities anyway, even if they are not THAT special.
Haters won't like that, but the gomu gomu no mi is and is going to be very useful and powerful either way, even more so with awakening, cause right now his basic gears, that mid range capability and extra agility already seems to be more useful than the most powerful Zoan hybrid, also cannot forget that Kaido in base is an Ogre, who's >> to humans, so if you further abstract the fruit's user from that, who's exceptionally powerful, you've got:
AdvCoC gomu gomu no Luffy > alternative advCoC dragon hybrid Luffy (even w/o G4 already).
It's getting even better if Kaido's awakening will be stamima time limited and ends up being around as strong as Boundman in terms of proprtional boosts, while Luffy has not even awakened yet.
But wait and see, it could also be that it completely shits on G4 for all I know.