I'll touch base on the software update to nougat. Software updates usually seem to cause problems, battery life goes down, glitches are there now, and so on.
As I've said before, I don't think it's just by chance Samsung updates phones just before the next version phone is released. Anyone notice how the complaints of phone not working now, I want to go back, battery life sucks, and so on since nougat was released. It's this way everytime, can't wait for the new software, what's taking so long, then it gets here and the complaints start pouring in.
So this guy has a point, but instead of wanting faster updates maybe push for the capability to revert to previous software, Or maybe don't force the update. But a perfectly good working phone don't sell new phones.
As far as battery life and speed of phone goes, that's nature of the beast. Batteries wear out, probably the number one reason there should removable batteries. Speed also slows down after time... A FDR usually takes care of the speed issue, but who wants to do FDR all the time.