I'm taking the plunge and separating the code into pluggable modules, if only so that I can test one part of this massive refactoring at a time.
The introduction of Playfic has encouraged me to step up my game. Supporting I7 extensions is a great idea, and while automatically importing them into Guncho is a while off, my design already includes a way to share extensions between realms, so I can at least import them by hand.