I think for a game to be considerd the GOAT, it
has to be at the peak of technology for it's time... and it has to have a great story, and great presentation... and geat memorable music, and great gameplay of course
Look at games like Halo, MGS, and Zelda:OoT... these are conenders for the GOAT, why? Because they have the full package. Games like Metriod Prime and Soul Caliber which are considerd great, still wouldn't be on anybody's list as GOAT because it's missing some element...
That's how I see it at least. I think Mario should stay Mario, even adding the squirt gun was kinda off imo... but I do think more games in the future need to start running on 3-4 year development cycles and start making sure that it's near perfect in all elements. It's sad to see all the great concepts today rushed.