It seems a little presumptuous to assume there will be an upgrade. I suppose it depends on how you look at it, but if they want it to be a home console then historically they haven't done upgraded models - cheaper models like the wii mini or the nes top loader, but those are arguably downgrades. In terms of handhelds, it's a different story. It's interesting to think about. I think it would be hard to fracture the userbase with a system that costs $400+, but I suppose if sony and microsoft can, then they can too. I'd be interested if they had an "upgraded dock kit" or something so instead of being a glorified usb c dongle it has some sort of coprocessor in it. Battery life aside, the extra performance (and resolution) would probably be more important in docking mode anyways, and that way people don't have to buy an entirely new system, and it would be easier to justify a new dock - current docks are what, $80-90? that means if they go for twice that then it's ~$200, cost of a new 3ds on release, and you get to keep the old one around as a backup or use it somewhere else.