Check your back catalogue, Nintendo. The Nintendo GameCube has a fantastic library of games and quite a lot of them haven't seen the light of day since. This article lists ten games and series that started and unfortunately ended on the GameCube. Therefore, Star Wars: Rogue Squadron doesn't count (since it started on Nintendo 64) and neither does Metroid Prime (since it has a sequel on Wii). Anyway, I hope you enjoy this list of long-gone but not forgotten GameCube exclusives that definitely deserve sequels.
Want Baten Kaitos and Donkey Konga
Didn't Starfox Adventures make everyone say, "Never leave the Airwing?"
I see a significant lack of Gotcha Force!
Viewtiful Joe 3 would be a peach. Viewtiful Joe 1 & 2 were a blast, the spin-off's less so - though not terrible. I'd love a true sequel to launch exclusively for the Wii U, make use of the Gamepad somehow. Eternal Darkness of course needs no mention, and a sequel I hear may be under way...*drool. Also, Wave Race (N64) was an inspiration, its sequel (Blue Storm) very good, but perhaps a step backwards from its predecessor. Now, can you imagine Wave Race U...that water, THAT water, those physics, online enabled, and all wrapped up in HD/60fps!
Star Wars Rogue Squadron II: Rogue Leader, but not likely as Factor 5 is no more in business.