I
don't know why, but I keep thinking of that trophy description for K. Rool and keep imagining that he will be in the next DKC, but not in the way you'd imagine.
Like, K. Rool tries to make his glorious return to terrorize the Kongs, but a new, much worse villain steals his thunder in the middle of it. Outraged at being upstaged, he (temporarily) teams up with Donkey Kong to kick the new villain's ***.
....then when the new villain is defeated, K. Rool steals whatever artifact they had that was the source of their power and becomes the final boss since the alliance is now terminated.
It could even be role reversal where DK is normally the one giving piggyback rides to the other Kongs, he hitches a ride on K. Rool's back if need be.