Nah, after a couple of weeks with the phone I'm right there with you. I was originally considering the Plus, and opted for the 6 after getting hands on at an Apple Store. It's a slick, gorgeous phone, but every time I pick up my old 5, I marvel at how much of a smarter and more suitable screen size it had. I thought the 5 to 6 transition would be more like the 4 to 5 transition, where looking back at the 4 makes me wonder how we ever dealt with the screen size. I was really surprised the first time I picked up the 5 again and thought, "Hey... this is a bit better than the 6..."
Overall it's a pretty minor quibble, and the 128gb of storage is more important to me than a slightly superior screen, but it's really a shame we probably won't see another screen that size in future iPhones. Hopefully the next one won't be so damn slippery at least (my only other complaint).