I would lie to be able you have Mii's in all of the modes of Mario Party 9, but I also would use the feature quite that often. I like to have options on characters though.
Miis should just stay in a few modes in Mario Party 9, I meant they don't need to be playable in the Party and Story Mode.
I rarely use Miis in Mario Party 8, so they should just stay in a few game modes.
well, mario kart wii had them with voices, but even so, mario super sluggers fixed that with them being voiceless, so i guess they could still be voiceless