If we want to play with numbers--

if both a 470 and 500 expand to 1.5x their diameter the cross sectional area of the 500 will be about 14% larger than the 470 with about 10% more energy.

Is this a markedly better round for game? Can you tell by shooting enough game with both? I'm no rocket scientist but the 500 sounds like a better hammer to me.Always Kill 'em quicker if possible---

As for bigger than 500NE--
If you can handle the recoil of a 577/600 class Double and use the second barrel pronto then go for it- You have my admiration.