I think I have got more used to the plus over the last year and agree with the portability part. If I could I would have both, but on a daily basis the battery was the main problem after the luxury of the plus battery and I had become too used to that. Love the 6s though.I don't disagree with most of your points.
On your last note about getting more for your money, it reminds me of the whole agreement over full size laptops (14"/15") vs. ultraportable laptops (11"-13"). People make the same claim that larger laptops have more value: larger screen, bigger keyboard, more ports. But they don't realize that *portability* is an invaluable feature that, to some people, matters the most.
For iPhones, some us prefer a real *mobile* phone over a miniaturized iPad that can make phone calls. Not implying there's anything wrong, just to make a point.