I think this would be a useful tool – even just in general, not just to review link but also offline use.
I understand there may be issues if the part published inherits anything from a higher level, there would have to be some sort of rules for what gets published along with the selected portion. Established rules could help solve this like you could only publish full chapters, or full sections, and all non-page content from the AU level will be published, all non-page content from a higher level will be published, or these last two could just be any inherited content of the published selection will also be published.
I mean, yeah adding special buttons that end up needing to be removed and adding in custom backdoors and developer pages is well and good and works and all, but why create extra work if there is a simpler alternative??
Regardless, everyone has to publish their course. It would just be super handy to have a publish setting that says publish all content or publish selected content, and if selected content is chosen a checkbox list activates that lets you choose the chapter(s) or section(s) you would like published and then just have to hit go and it does it.