Played with the 7 Plus today and this is the first time I've used a feature on the iPhone that I absolutely hated. It is, of course, the entire bottom section basically being a button. Feels unnatural, awkward, and reminds me way too much of the Blackberry Storm. In fact, someone here mentioned this new design pre-release and joked about the Storm, and I responded that that it obviously wasn't going to be that shitty. Now, that's true - it isn't - but I guess it reminded me a lot more of the Storm than I expected, and I did not enjoy that.
I think I'm sticking with my 6S Plus. First model I'll have skipped since the 3GS. If the 8 still has this design, fine - there are other reasons I'm willing to wait - but I hope it goes away.