I'm a HUGE supporter of Cranky Kong, and he's my most wanted character from my favorite franchise, the DK franchise. Do I expect him? Not one bit. But I do feel he is the most unique character from the DK franchise, and has the most potential for a creative moveset, while at the same time he represents the oldest of DK games and the newest of DK games.
Cranky is also one of the most prominent characters in the DK series, having appeared in more games than either Dixie Kong or King K. Rool. And in most games he's in, he's a key character, and in terms of NPCs, he's essentially the Rosalina of most DK games. Very important. But I feel what makes him most deserving of all are two games, the very first Donkey Kong for arcades, and the latest DK game, Tropical Freeze. Currently, the DK roster doesn't really properly represent either of those games. DK pulls more from DKC1, and Diddy from DK64. But Cranky can pull from both of those games rather easily. Sure, Dixie could represent Tropical Freeze pretty well, but she's also playable in DKC2 and 3... DKCTF is the only main series DK game where Cranky is playable, so if he's included, he'd be the best character to represent it.
Sakurai can sometimes pick unconventional characters, sometimes unexpected ones that the fans aren't even asking for. And he usually goes for the ones that are unique, and an octogenarian 8-bit obsessed fourth wall breaking gorilla is pretty dang unique. And I'd love to see the old ape fight against his long time rival for the first time since the arcade days.
The one downside, we already know he appears in the returning Jungle Japes stage as a background element... but let's hope that doesn't make him impossible to join.