I am not going to talk about other things, I just want to explain you that... you can take screenshots now with only one finger, you go from power to volumes in a second, you have them on your reach if needed. maybe it doesn't sound obvious to you, but try to take a screenshot on other Windows Phone with one finger? you cant.
You never thought about it? maybe for you it's bad placement but those things you just get used to.
I mean taking a screenshot with one finger is faster than moving your fingers and hand or using both hands. maybe for you is not critical but as you can see, there is a reason why powerbutton is in the middle. you always start by pressing the power button on 950 anyway.
Anyway your other words are just your opinion, and some can be improved with updates and all. but I wanted to comment just no that power button issue., maybe you already got used to it? maybe you already sold your 950, but I wanted to explain you a logical thing about it. you only need to get used it to it, like you get used to many things when you are in a new place, new house, new bathroom, new door, new anything can have different layouts and configurations, it doesn't mean it's bad.