Thanks for taking the time to write this up. I would agree with “Blender has a very strange user and developer experience when it comes to operators and their properties”! It would help new addon developers if there was better user documentation on both how operators and their properties work, and why it is designed that way.
Interestingly, I have used the redo panel approximately… never? That might be on me being a relative Blender newbie, as my focus is on VSE these days. I looked up the key to show it (F9), and if I hit that after using my operator or @tin2tin’s add outline, it just shows what I assume is the panel’s title, eg
I guess to get options to show up on there they would have to be added as *-Properties to the operator itself?
It’s also interesting (and, er, not obvious!) that there’s a difference in which part of bpy.types
a property is saved makes a difference to how it gets stored. Are WM-properties persisted in any way?
I ran into something similar wrt persistence of properties/preferences, and asked some questions in another thread:
which I still have some questions outstanding from. I must confess I am kinda confused rereading that thread- and I wrote it!
Blender is great from both a user and a developer perspective as TMTOWTDI; but it does make things potentially confusing. Lack of clarity or explanation from the official documentation and tutorials kinda ends up leading to cargo cult / “change something until this [appears to] work” programming-- at least I must confess that has been my experience!