What Yapua said :)
To add to the "13GB" thing, also, I'm making every attempt to keep the filesize of the game below 2GB because any larger than that and Android users wouldn't be able to play on a single file. This is the reason for the paperdolls in the game, and why I use a lot of layered assets.
It's for a similar reason that you don't have the ability to edit NPC skeletons/rigs in-game in pretty much any AAA game you can name. If a multi-million dollar project can't do it, why would you expect a solo dev to be able to do it? ;P