So...I will admit I'm probably jumping to a lot of conclusions...but hear me out.
So if we take this new Mii related stage as anything, that would be 2 stages devoted to Miis. I firmly believe that Miis will be included as customizable playable characters. That can also relate to the first trailer leak that also included Pac-Man.
So if we consider Pac Man and Miis, that would add onto the total newcomers, making it a whopping 7.
If you consider the Palutena leak, which mind you, has NOT been proven fake yet, that would be newcomer number 8.
If you consider the concept that Fire Emblem will get a newcomer (which is certainly likely), that brings it to 9.
If you consider the retro character (Takamaru, Lip, etc...) that many expect, that brings it to 10.
If you consider Mewtwo, the sole remaining almost shoe in, that's 11.
K.Rool and Ridley, two very much requested newcomers, would bring it to 13.
Basically...what I'm saying is, is that if there are any more "out of left field" character, that we may not see certain highly requested characters. Mind you, I will admit that I am taking a lot of liberties here. However, there is a possibility that one or more of the highly requested characters may not make the cut. Assuming there aren't any cuts.
I will tell you all, that if we don't see K.Rool, Ridley, and Mewtwo make the cut, that I myself, no matter how unique the newcomers, will consider this a failure newcomer wise.
That said, the next few reveals may turn the tables on speculation. We have no idea who we'll see next month in the Direct. April and E3 are incredibly important. I can almost guarantee that we'll see a 3rd newcomer aside from Pac and Miis (assuming we get those two at E3 to start with). Whoever that newcomer is will determine what direction we're going.
Because E3 is a Western event, I would certainly not be surprised at Ridley making his playable debut. However, if he is not the one shown, I will be a tad worried.
I'm not trying to be pessimistic, but this is the reality. If we get anymore anomaly characters, then we may not see one or more of the top characters.