SharkLord
Smash Hero
I mean Callie never punched anyone in the face but Callie BrawlerHonestly I feel like the main advantage Shantae has is being more "Casual" friendly since even casual players know her specifically and she already has a spirit in the game, meaning she has content in Smash already.
What Touhou has is a lot of variety for content and predating Shantae as the "Oldest Indie series" around. I consider Touhou a more "Hardcore" series in the sense that fewer people actually played the games compared to Shantae but it has a stronger legacy and IMO gives it stronger chances than most possible Indie reps. Shantae would be great in Smash and in an ideal world, both her and Reimu would get in the roster but unless there's more passes, it may likely be Reimu who will fill the big indie game.
And people keep saying Reimu would be good as a "Mii Costume" but no playstyle fits her unless they pull an Aerith Mii here. If we had a Mii mage character then I could see it(Sidenote I am surprised we don't have that) but unless you want things to be really wonky, a Reimu Mii Costume is unlikely.
But yeah. While having her as a Swordfighter is possible, having her as a fighter would be much preferable.