A super computer that cannot only emulate every game ever made and yet to come, but has slots for every cartridge and kind of disc, as well as customizable parts to make new ports for new kinds of cartridges and discs. Same for controllers and memory cards. Fully realized VR, built in arcade sticks and buttons, and an Altimit OS-esque desktop.
Alternatively, a console just powerful enough for hobbyists and circles to make games for (around PS1/N64-previous quality at best). I know there's been attempts at this kind of thing, but I want one that is actually successful. I want to buy new games that aren't AAA or Steam indie stuff. If someone could pull this off, it'd be amazing.