In regards to competitive, I think it's quite possible heavy characters might fare better this time around. Definitely nowhere near top tier, but I think the changes to aerials and lags in general are going to mean characters like Ganon, Ike, and Bowser might fare a lot better. But I also want him even if he becomes this game's Sm4sh Jigglypuff or Brawl Ganon.
Relevancy has always been K. Rool's greatest weakness, but... and I realize I'm not saying anything that hasn't been said... his Mii costume in 4, Ridley's inclusion and all veterans returning via fan demand, and the timing of the ballot and this game's development have made it so that this is the first time that K. Rool has truly felt like more than a longshot dream and an actual possible, if not likely, newcomer. But I've been burned enough times to know to never count anything as a guarantee, short of a reveal trailer. And if he doesn't make it, then we'll all continue supporting him for when DLC gets confirmed.
The King has been my most-wanted newcomer ever since Diddy was confirmed for Brawl. Well, him and Banjo, but if we're talking strictly Nintendo I think K. Rool is quite possibly the last truly glaring Nintendo omission in my eyes. Here's hoping.