It would be nice to have multiple tokens for a character, and an ability to switch between them in game. This could be useful for:
more interesting status effects (dead, prone, etc.) - Example: I could have a token of a soldier, and a token of a dead bloody body. when the target is killed, i can just toggle the token to the second graphic. This saves time over having a hidden body token that needs swapped in.
Character side visual changes (disguise, changed clothes, polymorph, etc.) - Example: players would enjoy being able to swap around the visual style of their own characters
GM side varried enemies. - Example: a 50 goblin fight is visually boring, especially when i have so many cute and fearsome goblin png files! multi state would let me quickly clone out a few then vary their look, rather than have to keep multiple versions of the same monster in my vault just for visuals.
How it could be implemented: use the existing character build system, and simply allow more than 1 file to be uploaded, with the first one being the default (or a check box). have these files cumulatively add up to the file size max, so you dont have a runaway storage problem of too much data on a single character.