@msteffens Sounds promising.
To echo @Ben_Wah comment, editing (deleting, moving, extracting subsets of) document PDF pages is a great feature. When it gets down to business and reference, having a shorter or reorganized PDF can make it far more efficient, e.g., getting rid of cruft, illustrations, chapters, or just keeping a key page or pages from a doc. I.e., make the document one’s own for the task at hand.
Also, on the source citations (linking). Highlights does this well, but superficially. Highlights (pleasantly) surprised me with links in the Notes to the source documents by default. Awesome. Unfortunately, the links do not inherit to subnotes that I split. So the source reference gets lost. Ouch. I would suggest by default (?) having the source document inherit to subnotes, even after edits. That way the source material, inspiration, reference remains handy.
Finally, I am glad you are focused on workflows. I believe the PDF programmers don’t eat their own dog food, get lost in the weeds as they program. For the bigger companies, the feature list is probably all about marketing (new sales, laundry list), not real workload realities, and the programmers 1) don’t know any better (are not part of the target market), and 2) just do what they’re told. So if you can stay on target and raise the bar, that would be great!