8 Players is nice and all, but I have 10 Wii Controllers? (plus the Tablet, my two Pro Controllers, and my multitude of GameCube Controllers/Wavebirds).  What are you doing for *me*, Nintendo?

:D

Buy Bomberman and make a 30-player local Bomberman game.

I actually plan on doing 8-player smash quite frequently. My wife and I like to play, my kids like to play and all the neighbor kids will want to be playing, just yesterday we had 10 people at my house that would have enjoyed playing (if it was already available). I only own 3 gamecube controllers, but I have 4 pro controllers so we'll probably do Gamepad, 4 pro controllers and 3 gamecube controllers most of the time.
8 gamecube controllers isn't an option for me (even if I bought 5 more) because I buy all my Wii U games digitally so I have a 2TB external hard drive taking up 1 of the 4 USB ports. This is the first time I've found a legitimate downside to downloading all my games, I really hope things like this don't happen too often.

Perfect. I have 5 Wii remotes and 4 gamecube controllers. But one Wii remote has a cracked sensor, and my dog chewed on the sticks of my orange GameCube controller.

My condolences.

Have you considered switching the sticks out? I don't know how difficult taking apart a GameCube controller is, but I'd totally give it a shot of I had the Spice colored controller.