Just wanted to add a couple ideas regarding possible improvements to Yooka-Laylee's longevity.
1. SPEEDRUN SYSTEM (Time Trials) - Platformers have always been very popular amongst the video game speedrun community and have stood the test of time. This can easily be observed by witnessing the consistently growing audiences for it through streaming services like Twitch. My suggestion would be to implement a "timed" playlist for completing each individual world and full-game. Then, (if possible) provide an Online Leaderboard for players to compete through.
2. Rextro Online - Following along the same competitive theme of implementing a leaderboard, I think many would enjoy comparing their "Personal Best" scores with players across the world. This would also allocate more purpose for experiencing Rextro's Arcade within the story-mode.
Really looking forward to seeing what content Playtonic adds in future updates and would love to hear some opinions relating to my suggestions above. Happy gaming guys!