The fundamental problem with your topic here is that you are grouping "Nintendo Fans" as a collective. If someone has flip-flopped, you should call them out... ie, "TheLastStarFighter said graphics don't matter but now he's talking up MK8". The problem is, I doubt many Nintendo fans have flip flopped. The stereotype has just changed.
I've enjoyed Nintendo games dating back to their 3rd party days on ColecoVision, and Nintendo has almost always been at the graphical forefront. From Donkey Kong, to SMB, to SMB3 to Zelda:ALttP to F-Zero to DKC to OoT to M64 to Zelda:WW. The only time they haven't been is on the SD Wii, but even there SMG and Xenoblade pushed that system to its limits. I like Nintendo games, and I like nice graphics, and I think most gamers like both too.
As to your specific comparison, I do think MK8 is as impressive as Driveclub, and in some ways more. A flat sheet of metal is easy to make look good. Mario and his cart are far more complicated. Mario is fully animated and "human", which is tougher to do well than static flat metal. And you were very selective in your image choices to make your point. Both look great and are graphically impressive in their own way.
