wow, that is awesome stuff.
Only thing I wouldn't mind is more fine-grain 'event' control of pre/post scripting of various plugins (pre-CREATE_OCR_INPUT, CREATE_DISPLAY_IMAGE, CREATE_THUMBNAILS for example, but not the others in Page Process) on top of an independent 'script' plugin...which might already exist and I haven't uncovered it yet.
(example usecase I was playing around with was deskew/despeckle as a script, which as a proof-of-concept works on the end-result image, but since scripting happens at the end of page processing the ocr/other plugins ran first before the cleanup) -- once the community code gets released, going to look at adding options directly to those plugins for this feature rather than scripting, but as an exercise to try out scripting it helped.
Regardless, the flexibility provided with this plugin is limited to the entire programming language, so you have a lot of options!
Thanks for this feature!