Plasma King N
Another Pokemon Trainer? I doubt it.
N chances: 0.01%
N want: 0%
All Popular Newcomers
There's a little bit more thought needed here. I think this should be called "only popular newcomers" based on the description. The ones that are wanted and we've discussed extensively.
So the thing is that the series most likely to surprise us was Pokemon. And it's possible there's another surprise in store for us still, but I doubt we're getting another newcomer Pokemon. It's probably Jigglypuff, Mewtwo or both. But there's a chance there.
Fire Emblem is another series with a possible surprise... but I really doubt it's anyone other than Chrom, Robin, Lucina or Roy.
As for other series... we've discussed the main possibilities... New series could still hold a surprise though. While I consider Isaac unlikely, he's popular. Shulk, Pac-Man and Takamaru are popular and highly discussed.
Some of the possible surprises on that count are Rhythm Heaven, Advance Wars, Chibi-Robo, Custom Robo, Fossil Fighters, Pilotwings, Ouendan/Elite Beat Agents, The Last Story, Pandora's Tower, or some of the retros like Sheriff, Duck Hunt Dog, etc.
I doubt we'll get caught with our pants down like we did with Greninja though with someone we've never talked about specifically.
But the chances that we'll get at least one of those less popular/less expected new series is pretty decent, there are a lot of options. The chances we'll get a newcomer for an existing series that we're not expecting is pretty low though, since Greninja is already there, and Pokemon was always going to be the hardest to predict.
Only popular newcomers chances: 15%
I think there's a high chance we still have some surprises in store, but I don't think Sakurai is as unpredictable as some think.
Want: 70%
I accept that some of my ideas are not going to happen, but there are definitely some surprises that I'd be pleased by. At the same time, most of the ones that I'm not personally a fan of are characters I'd actively prefer not to see. Balancing that, there are more I'd rather not see.
Predictions:
Chrom AT - 5%
This would be seen as an insult, so I doubt Sakurai would do it. Lyn is an AT, but she was also quite old news when it happened.
50+ character roster - 10%
I really don't know what people are thinking about this. I personally think we're most likely to get a number in the mid to high 40s, but low 50s is still quite plausible. We definitely have a bunch of characters unrevealed unless Sakurai absolutely butchered the Brawl cast, and it's highly doubtful that we've seen the full newcomer roster. We've gotta have at least 2 or 3 newcomers being held back. But even if there are no more cuts, we'd need there to be 7 more newcomers (or Mewtwo/Roy). That seems quite optimistic to me.
Nominations
So I have 15 extra.
Bowser Land x10 (I assume that means a Bowser-themed stage?)
Medusa Rerate x5
Hades Rerate x5
As Palutena's chances have risen, their chances should have fallen. So I think they're quite overrated now.