The only place I have a minor issue with your comments is your total opposition to the rope luff.
PROPERLY MADE, with multiple pieces of rope, of properly selected lengths and diameters, SEWN in place in a well made pocket, in my experience it can do just as good a job at bulking up the middle of the sail as a foam luff. (Note, there are a LOT of caveats on that...)
Improperly made and shaped neither a rope NOR a foam luff will do a good job. I have seen foam luffs that were not properly tapered, and resulted in terrible sail shapes when furled.
On my SM I have a foam luff, on my old boat I had sails with both foam and rope luffs, and would be very hard pressed to say there was a dramatic difference between them in furled sail shape.
I suspect, but can not prove, that a foam luff will be longer lasting just because it should result in a smoother roll. I have never had a rope luff chafe through... but I can imagine it happening.
We always have to make compromises when we ask one sail to do multiple jobs. They are never going to be perfect...
Cat Island, Bahamas