>>716467484 (OP)Most comparable to Fable 3. He goes out on his own individual missions of mayhem about the Kingdom, but cute and all-ages y'know.
You can focus on his magic, or melee, or weapons (usual mag, str, dex split), but exp. capped such that you can't have everything. All-in on 1, strong combo of 2, or jack-of-all/master-of-none. All lore-friendly and referencing Bowser's many zany powers and schemes; fire/dark/summoning magic, spikes/claws/horns/shell/size, bullet bill/bob-om/chain chomp. Playing like Fable 3, Ratchet&Clank 1, and Odyssey.
There's also a fleshed-out real-estate aspect like Fable 3. The currency is the classic coins, but their value and Bowsers' options are influenced by Fear. Based on his performance and decisions in missions the citizens fear Bowser. If he isn't evil enough, the citizens get the courage to charge rent, raise prices, refuse progress, or take back property.
Since it's Nintendo, you can choose to be nice to everyone and Goombas and Koopas like his lordship so donate items/funds in order to make good or bad both fine options.
Missions could be anything: Mario Galaxy-like planetoid, Zelda-like Dungeon, boss battle some badass Toad/Mario/Luigi, platforming time-trial, waves of goomba/koopa survival. Not sure how they're presented; linear story, branching path, quest board, whatevs.