Banjo Kazooie/Tooie are two of my favorite games, hence why I want to play Yooka Laylee. This drama aside, it looks like it will be goodIf you have a rock solid game foundation, it will appeal to all ages, and that's what Banjo Kazooie has going for it (Jon goes in exhaustive detail in his 'Nuts and Bolts' review about why that game shits on what made the original so great).
Alternatively, Rareware also basically developed a game nigh-identical to Banjo-Kazooie except it was based on a Nintendo IP. Donkey Kong 64 is also very much a 'collect everything' kind of game but it made you work your ass off for every last one - most of the true game challenge is in the psuedo-puzzles and minigames to get these things.
Or, to provide a completely different example, the kirby games. In Crystal Shards, Stage 5-4 is a bright and happy mall type place. Stage 5-5 is a dark and depressing factory with one of the most iconic themes in the franchise (Factory Inspection) and the setting for Stage 5; Shiver Star, is widely believed to be post-nuclear apocalypse Earth. The most recent one; Planet Robobot, is fairly standard campaign for kids stuff with gratuitous extra lives. But if you go deeper, the story is shockingly dark (the guy you think is the main bad guy is actually an innocent, mentally broken man tricked by a supercomputer into giving it sentience, whereupon it casually states its intentions to literally kill everything that ever lived - and that's before you even see its true form as a reality bending mechanical star-comet that makes creepy cat noises) and the challenge modes feature far harder bosses intended for longtime Kirby fans (because no kid is going to know the Dark Matter Clone boss is from Dreamland 2, the first time he's shown up in that form in over 20 years). But, you know, the bright colors and friendly shapes everywhere totally don't give any hints to just how horrifying or mature oriented the game's entire foundation is. Even with 'Factory Inspection' being reused wholesale as 'Power Plant Inspection' - kids totally love soundtracks that sound like a perpetual train crash into a piano factory.