I'm waiting to see about Kirby Super Star Ultra modes, like "Revenge of the King". If that features playable Dedede, I will be happy. If that features an all-Dedede crew on the Halberd, I will be happy. If it's a mini-game collection, I will be mildly disappointed, then happy for ten minutes, then disappointed again.
Really, I think that King Dedede has a better chance of being in his own game than Meta Knight. He's more of Kirby's rival now than an arch-nemisis, and he's pretty darn awesome at that. Meta Knight's another rival, yes, but...there's just something that would make Dedede more appealing to a mass audience. He's like Wario, but with a hammer...and as a penguin. He's just as much of a standout character as the oafish Mario knockoff...I'd give him good odds, at least better than Bowser's, at getting his own game.
Or at least a game that he hijacks from Kirby. XD
As for Meta Knight, my faith in him was a bit shattered by Brawl and how cheap Sakurai made his own creation (seriously, dude's got Infinate Dimmension Cape...HOW DOES I COUNTER?!), but then I play the Revenge of Meta Knight...I miss that old MK, I do...