The "paradigm" is that each data file is contained solely within each app (with some exceptions, which often don't work properly) and this can give rise to some really irritating situations.
As Nige321 says.... "Please give an example - if you mean sandboxing there's some really good reasons for it..."
One has to appreciate that it is basically a media player / web browser and such, not a computer.
Again, what Nige321 says...."utter tosh"
Your beloved Android is "not a computer" either !!!
But because most IOS apps are severely crippled functionally
Erm, you do understand its developers who write apps, not Apple. Therefore if you've got grief with the apps, its the developers you should be moaning at.
And as someone who has recently taken ownership of a Blackberry Bold 9900, I can tell you, both the Apple platform and the Apple app selection and quality is so much better than the Blackberry equivalent (you have to reboot the thing each time you want to uninstall an app ... I mean, come on !).