I'm think that in the future (not immediate mind you
), we may want to add a new pretty-print plugin type. One that can be used in the"traditional" PluginRunner dialog setting (for debugging purposes), but can also be "assigned" via the clean source settings using a combobox populated with installed pretty-print plugins.
I've been mulling the idea around in my head for a bit. And it'll probably mull a little longer. The bottom line is: Sigil's not overly concerned with making your code look "pretty" any more. It's more concerned with not breaking anything. We are, however, dedicated to providing a framework that offers users a way to manipulate their code in any way they see fit--through a robust plugin system.
My two cents anyway.