Originally Posted by Luca
It's on more fronts than UI design (which is still declining). Overall performance is bad, and updates seem to make things worse every time. My parents are both on older iPads (my dad has an iPad 2 and my mom has an original iPad Mini) and they have both refused to take any further iOS updates past 7. It's a good thing they're sticking to the old software too, because my wife's own original Mini is almost unusable now on iOS 9. We're talking 5-10 seconds of lag from when the keyboard comes up until it starts working. Every time an update comes in, I hope that they've fixed it, and every time, it only makes it worse. But there's no way to roll back so I'm stuck.
A clean install of new releases of iOS (after backup and return to factory settings) can help with this problem. Fixed it up on my iPad 2, in any case, which was not working very well with the original iOS 9 install (not clean - actually I had never done a clean reinstall) and then worked happily after the reinstall.
Actually, I am not sure that I would fault Apple at all on this particular issue. They are actually pretty dang good on backwards compatibility. If my iPad 2 runs well on iOS 9, when it was originally released on 4.2, that is quite good. It is unrealistic, however, to think that it will run as snappy as the latest Air 2 on the same software.
[Full disclosure - I actually also own an Air 2 now and have given the old iPad 2 to my young son for day-to-day use. That said I did use the older iPad just yesterday, and it still felt pretty good, though clearly not as fast as my Air 2]
I do fault Apple for some other recent software issues though, especially the end of the line for development of Aperture and the rise of Photos. What for??