This is an old post, But thought I would bring it back since we are on topic about it again.
There are a only handful of developers out there that I can think of that Nintendo would actually have work on the Donkey Kong franchise whether it's Country/3D/Spinoff.
1st/2nd Party Development Teams:
Retro Studios:
- Donkey Kong Country series
- Metroid Prime series
Nintendo EPD:
- Super Mario series (2D/3D Games)
- Donkey Kong Jungle Beat
Next Level Games:
- Super Mario Strikers series
- Luigi's Mansion series
- Punch Out !!!
- Metroid Prime: Federation Force
3rd Party Development Teams:
Ubisoft Milan/Paris:
- Mario and Rabbids Kingdom Battle/Donkey Kong Adventure DLC
Playtonic Games:
- Yooka-Laylee
- Yooka-Laylee and the Impossible Lair
I'm sure Nintendo's in-house development teams are up to the task, But I would prefer if the Donkey Kong IP got handed over to a Western developer seeing how that's really the only time that the series has actually thrived (Rareware & Retro Studios), I know I sound like a broken record, But my developer of choice would be Playtonic Games with co-development by Retro Studios (That is If they have the extra man power for assistance) to offset Playtonic Game's smaller development team.
Retro Studios have shown that they are more than capable of carrying the franchise, But with them taking over Metroid Prime 4 development it may be a while if we get anything DK from them (Unless that was what they have been working on all those years or worse case scenario it got cancelled).
Next Level Games doesn't get mentioned much, But they have shown that they are very capable of handling Nintendo's IP and making great games with them, The Super Mario Strikers series is really fun and they did an amazing job with Luigi's Mansion 3 which I feel will be the last one from that series in a while, So it seems like the time is ripe for them to move on to another franchise and Donkey Kong seems like a really great fit for them.
Don't know too much about Ubisoft Milan/Paris and didn't play Kingdom Battle because honestly for me the Rabbids were a dealbreaker and I don't have too much interest in the genre that they were tackling, But I heard it was still a great game and that they did a solid job with DK DLC, which Grant Kirkhope scored and the studio director (Davide Soliane) is a big fan of Rareware too.
I feel like these are the most qualified, likeliest and realistic choices for handling the Donkey Kong franchise and me personally hope it comes down to Retro Studios or Playtonic Games or and it's a long shot ,but if possible maybe even both, If neither of those are an option then I would love to see Next Level Games take on the franchise.