I liked how Rare's humor on the N64 escalated to be more dry and more adult-themed as time went on. First you had Diddy Kong Racing, which was purely innocent, childish humor. Then you had Banjo-Kazooie, which added some irony and satire to the mix. Then you had Donkey Kong 64 which added some sexual innuendo in with the satire. Then you had Tooie with it's more overt sexual innuendo and surprisingly dark humor. And then of course you had Bad Fur Day, which I need not explain.
Since this is a Banjo-Kazooie spiritual successor, I'd expect its humor to be on level with Banjo-Kazooie. But I wouldn't mind if they started out with more innocent humor than that and escalated it in future games. There's something amusing about the idea of taking a bunch of innocent, happy cartoon animal characters and running them through the ringer until you end up with a hungover potty-mouthed squirrel.