Unless I'm mistaken, as with the tiler, the mapper is intended to generate designs for the final game. The tool is not for creating custom playable stages, although that is an interesting concept. Proceeding with that in mind...
Pretty much all of the character sprites are completed, so no current need for a character creator. I feel as if any expansions to the game will be made known on a long term basis. Yet character interaction in an MMO will require some degree of visually unique avatars, regardless of the player controlling several story characters. However, I like the idea of an item creator for drawing, naming, and determining stats. That sounds really fun, miles more popular than the tiler and mapper, and of course Hull would select the best ones.