Those aren't exactly contradictory. The previous generation tends to be deeply discounted around the holidays. It could very easily be true that iPhone 7 sales are sluggish even though iPhone 6s sales are seeing a solid holiday sales bump.
As somebody who has repeatedly tried and discarded wireless headphones over the past two decades, I would argue that wireless is the past, not the future. Who wants to have to worry about whether their headphones are charged just to be able to listen to something?
I mean, intellectually I understand why some people might prefer to not have wires, in much the same way as I understand why some people like to have cars without a roof. I still wouldn't drive a convertible unless I can put the top up when it rains.
You know how the best camera is the one you have with you? Same goes for the best headphone adapter. The best headphone adapter for the iPhone 7, then, is my iPhone 6s.
The iPhone 6s had a Taptic engine. The jack was removed so that it can buzz in more ways. Yay.
Plusses? You mean the silly camera tricks to make people think it's a real camera or the new buzzing modes? I mean, if they had at least moved to OLED, that would be a meaningful improvement....