Don't forget that Risky's Revenge is what happened as DSI ware because it didn't make it through development/publishing over the course of the GBA generation, THEN was going to be episodic, THEN got an actual release.
Shantae games (excluding the original) are on a release schedule akin to Zelda games or Blizzard releases. Oh, they'll happen...just not when you expect them to.
Also, I'm definitely in. Wayforward makes great original releases, decent licensed stuff and the road to each new release is paved with passable shovelware. They have yet to let me down with a Shantae title.