Offline/Local play
I see tons of people complaining that they can't play with their brother/sister/friend in the same house because of the multiclient issue.
The solution to this is an option for local play. Have it so you're able to connect to the other player, well... locally via same wifi connection. No Qi or TC would be earned in this mode. It's basically free play with 2 players; you can change the game settings, game mods, etc.
I don't see it being too difficult to implement into the game. So, what are your thoughts?
[Insert stereotypical "this may have been suggested before, but..." sentence here]