it's a small idea but why not have Kartos do what he was meant to do and what I mean is help us travel the world.
so here is the thing Kartos only give us a ride to get a pagie as a price at the end of the challenge and that is all he does, but I ask why not have him also help us reach the end of the goal whenever we play his travel challenge whether we succeed the challenge or not at the end of the challenge we can reach a far off destination of the challenge in that world he could work as a fun way to travel around the world.
right now if you play his challenge even if you succeed in the challenge you go back at the spot where you meet kartos it's like you didn't even travel at all.
also for future dlc you guys can add a new type of collective item that could be used to trade for fun character re-designs Example: Yooka with a shirt and laylee with a hat(verity of color/design shirt and hat) or different colors yooka laylee or redesign yooka laylee to look like a new character, just fun option folks could get by collecting the new coolectible.
you can have Kartos give this new collecible by succeeding on his rides after you get his pagie first and by completing his first challenge(the pagie challenge) folks could unlock new routes challenge that helps yolks travel around the world in a fun way plus+ if yolks succeed on the challenge (what ever the route is) folks would get as a price the new collectible that could be trade for the fun redesigns.
why I think Kartos should have this? because personally speaking I think Kartos challenge and Rextro challenges are by far the hardest in the game and they are usually the type of challenges that could be more fun in the game if they had a goal price besides the pagies.