Don't worry too much. Palutena's fate won't be that devastating like Toad (who I already know wasn't gonna be in). Just remember, join together and wait for December, for that's her biggest chance. Besides, Sakurai gave us TL on the JP WW release date, and a nice Mario-themed pic on the JP Mario 3D world release date, so if the chain of Japanese events were to continue, then Palutena will be close. Like I said, KI anniversary was 12/19/86 in Japan iirc, for this year, that day of the year is on a Thursday. Earlier or later in that month is what I suspect her to appear.
But then there's also March of next year for the 2-year KIU anniversary too. Just don't give up, and stay hopeful. I'm sure she will be in the game 1 way or another at the very least.