Yeah! We could create a new island and species to fight, and then battle them while controlling the kremlings. They could visit some Kremling environments and this new island to have a mix of new and old. Also, the new enemy should be something even worse than the Kremlings, so to make the player not feel like he's controlling the "bad guys".
Also, I thought they could make a Brother's Bear platformer with some RPG elements.
A Diddy-helmed series or even just another game starring him is the most logical option, I'd say, to the point where I'd almost expect it to happen in a few years. I once had a crappy fanfiction idea for a game which basically consisted of a DKC story with DK kicked out so Diddy could take the forefront, but again, crappy fanfiction.
The DKC Atlas Forum is a place for fans of Donkey Kong Country to come together and discuss the classic Super Nintendo trilogy. Discussion of DK, Diddy, Dixie and Kiddy's other adventures is also welcome, so fans of the Donkey Kong Arcade games, the Donkey Kong Land series, DK64, Diddy Kong Racing and Donkey Kong Country Returns will find plenty to talk about here, too.