Would it be at all possible to implement something to manually adjust room sizes?
Sometimes you get a dungeon that's just near perfect but it needs a few little tweaks.
you can upload it into dungeon scrawl and edit everything
That's what I was going to suggest. And Dungeon Scrawl is not the only editor capable of importing these maps.
How do you upload to dungeon scrawl? Dungeon Scrawl does not seem to support the export options.
On the left side toolbar click the third button (Plugins) to display the Plugins pane. One of the plugins is "Import One Page Dungeon | Watabou".
Woah - that just made this generator even more incredible - thank you!