Because Win8 is being criticized, all OS's are equally unintuitive? Please. Win8 is in a league of its own, and the poor reviews reflect that.
I still have no idea how you switch off an iPad after using one for 20 minutes (we ended up just closing the cover and putting it away on the assumption it would sleep eventually).
...which it does, and is very aggressive with its default sleep settings. It can sleep for weeks/months with barely losing any charge, and wake up in less than a second.
Secondly, it's a handheld device. The power button is right there if you need it (how did you ever power it on?), but you rarely do. This is a perfect example of where minimalism makes sense for the form factor, and why the iPad's design was praised, and one of the reason it dominates the tablet market. Tailoring the OS for the product, removing features/adding them where it makes sense for the form factor.