Note to people: 40% is not low. I keep seeing people give scores like 30%-45% and accompanying them with comments about how you just don't see something happening. Or you gave Roy a score of 38% but also said "Chrom is gonna get it, Roy's not very likely."
To put it in perspective: The probability of being dealt a five card poker hand with a single pair in it is ~42%. So when you give someone a rating in that range, think: Would I be more surprised to see this character than I would be to be dealt a hand with a single pair in poker? If so, you're inflating your numbers.
Mii - The chances of Mii making an appearance, unfortunately, are much higher than the chances of me. Hyuk hyuk hyuk. Stupid puns out of the way...
Popularity/sales: The series of games starring Miis have blockbuster sales. Games starring Miis have sold 150 million copies. Even if you exclude Wii Sports from that for being a pack-in, it's still 70 million, more than any other unrepresented franchise unless you count some of the Mario spin-offs (Mario Kart, Mario Sports) as their own franchises. So Mii is the "character" with the highest sales by far whose series is not represented. Miis are also quite popular with casual players, and do decently in the Smash Boards poll.
Relevancy: Well, I kinda already covered that.
Design: There are a number of possibilities for a move set. It would easy enough to cobble something together from Wii Sports/Sports Resort, Wii Play, Wii Party, etc. The only issue that makes it more complicated is that Sakurai may want to avoid moves that are similar to ones used by Villager or Peach (although Peach really has enough to work with without drawing from Mario Sports spin-offs IMO).
I will say that an issue is that even if you do give them a move set, they're supposed to be an avatar for the player. And really any move set you give them kinda interferes with that aspect. When you're playing a game where everyone does basically the same thing (Mario Kart, New Super Mario Bros, etc.) you're just applying a skin to them and then it's like " I " am in Mario Bros. Or " I " am racing in Mario Kart. In Smash Bros, however, it won't be like " I " am a Smash Bros fighter. It will be like " I " am a Mii using moves from Mii games. So conceptually, I think making Miis playable actually interferes with what they're supposed to be. Giving them a move set makes them not avatars, but instead representative of Mii games. This would be a lot less so if they were customizable, but I don't think Sakurai wants to do that since that would be a nightmare to balance and consider for online play and so forth.
Competition: Since Waluigi has only appeared in Mario spin-off games, if he were to be limited to moves from his previous game appearances, his move set would also be quite similar to what's possible for Mii. While you could cobble together different sports-based move sets for both of them, I have a feeling Sakurai wouldn't want to do that. Because of this, Waluigi is the only character I see as directly competing with Mii. They could of course be made to be different if Sakurai really wanted both in, but that doesn't change the fact that if Sakurai had already decided on one, he would be less likely to decide to include the other (IMO anyway).
Sakurai statements/Nintendo branding issues: Sakurai may consider them too generic. He didn't integrate them into Kid Icarus much. Personally I find them a bit out of place in games like Mario Kart and New Super Mario Bros. In those games, they would fit better if they were altered more to fit the style of the games, but the cross-over nature of Smash means they'd pretty much have to be in their most generic form (clothing designs could have a little more freedom I suppose).
Also, Nintendo likes to control what happens with Miis. I do see this as a mark against them. However, Miis have been put in Mario Kart, Mario Party, Mario & Sonic Olympics, Sonic Colors, New Super Mario Bros, Sonic Racing, etc. So they're pretty ubiquitous. It's fair to say were it not for the issue of violence, Nintendo corporate would probably want to put Miis in this game without hesitation. On the violence issue I note that they used Miis for boxing and sword fighting (sort of) in Wii Sports games. In Nintendo Land you use your Mii to take the role of Link. So some level of violence is ok with them. The issue they have is whether Smash Bros is the kind of violence they shouldn't allow Mii to be associated with. It's certainly cartoon violence and it's not bloody and your Mii won't show any signs of being injured. So it's not the most worrisome use of Miis out there. It's worse than the sword fighting and maybe even worse than the boxing (if you consider taking one of Snake's missiles to the face worse than a punch to the face), but not really that bad IMO. They may worry about people beating up Miis that they give the faces of people they dislike. That seems like it could be an issue even with the games they've already made though (actually, I'm pretty sure my friends did that with Wii Sports Resort and the sword fighting game).
In the end I think the branding issue is a wash. It's not the best fit for Miis, but it's not that bad either and it will be a high-selling game so they have some incentive to put them in. So I think it comes down more to what Sakurai thinks.
There's also the "leak". It's prediction that was unlikely, but afaik they don't claim any inside information. But it was only right about 3 out of 6 characters being revealed during E3, only one of which was actually an out there prediction, which is a lot less impressive than people are giving it credit for (still decently impressive, but not so much so that it couldn't have been a guess). Even if the person did have inside info, the fact is that they didn't give us 100% correct info, and whether they're wrong because they had bad info or because they purposely gave us bad info (whether they were wrong/lied about the characters, or merely were wrong/lied about them showing up at E3), we can't assume it's correct.
Mii chances: 35%
I wouldn't be that surprised if they showed up, nor would I be surprised if they didn't. I give them a slight disadvantage since to me they don't seem to fit aesthetically and that Smash Bros doesn't perfectly fit with Miis either (as I mentioned in the Design section). They won't feel like proper avatars in Smash. I think probably Nintendo would want them in, but I think Sakurai has the freedom to say no and has some good reasons to do so.
Mii likey: (ok I had another pun) 46%
I don't like them aesthetically, but I think they could have a fun move set and it could be fun to play around with them. It would probably get old after not very long though. It wouldn't be horrible though. I'm mostly indifferent.
Owain: 4.2%
Who da **** is this? Obscure FE character is obscure. Of course, since somebody's giving him nominations, there are some number of people who will give him decent chances (10%-40%).
Nominations:
3x Jigglypuff
2x Lucario
1x Ice Climbers
I just wanna spread out some of the FE people, so I'm switching up my nominations on that basis. 3 of them in 4 days is bad enough.
What happened Roy? Oh yeah....GameFAQs.....
