One new series. Possibly more in 22+.
And Dyce, have you thought of any good explanation for why Metroid is the sole exception to the entire ordering rule of the list? Do you think they just didn't notice, or what? And why did they change how they organized the list for Brawl? Rather than a theory that was tailor-made for the icons already present, I want an explanation for why a rational human being would actually implement it that way.
I have no explanation for why "Metroid" is in place of what should be "Samus". I suppose there could be some reason, or maybe it is just a goof. I really couldn't tell you. It's just something you're going to need to take with a grain of salt, grin, and bare it.
Now, I think they use the series name now instead of character names because it makes the game and Dojo updates more difficult to track. I imagine that Sakurai realized to himself: "Hey, some of these die-hard fans of mine are pretty smart. Someone is going to eventually figure out my icon filing system, so let me make it less obvious and instead of using the exact character name, I'll use the franchise name and leave them something to chew on."
Notice how Sakurai likes to not give out complete information to us with any of his updates. He knows that there is a SWF, and he knows there are other boards out there where people want to talk about SSBB, so instead of basically teling us what's in, he's just leaving us with vague ideas to spark conversation, ideas, theories, and speculation.
Imagine that the AC icon was catagorized where "T" would fit in. We would basically KNOW that there is a character, and that character is either Tom Nook or KK Slider (Totakeke). But since Sakurai chose to go with the franchise, we have no idea who the representative from the series is, or even if there will be one.
Same goes for the "Touch! Gen"/"DS" icon. Place it where "M" would fit in... hmmm...
Mii? Fit it anywhere else... most likely, there is no character for it. Now where's the fun in that?
So in short, I think Sakurai is doing this because it's fun for us and doesn't give him away. Period.