I'm going to go with SSJ4 Gogeta on this one.
Kid Buu had the power to destroy the Universe, even stated by the Kai's themselves. End of Z Goku at base form was Kid Buu's level. x that by 400 (SSJ3 multiplier) and you get a warrior 400 x the strength of Kid Buu. When Goku turns SSJ4, he gets all his powers back and SSJ4 is 10 x that of SSJ3 power (SSJ4 Muliplier). Omega Shenron is miles ahead a SSJ4 Goku, and SSJ4 Gogeta is miles ahead of Omega.
I used to think like you.. but then i realized that there are so many wrong statements on your post