Failed Gaming Concepts/Ideas That You Wish Were Successful

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Sega Saturn.
It had obvious problems, but it also had some really excellent games like the Panzer Dragoon series, Nights into Dreams, Burning Rangers, Radiant Silvergun and Powerslave/Exhumed.
I even liked it from a hardware point of view; it may have been hard to develop for but it was internally fascinating and externally attractive.