One thing I always thought would make a brilliant addition to Android is individual app permissions. Some apps I don't want to be able to use 3G data at all. Some that are just greedy with their permissions need to be put in their place. All of this is in Android version 4.3, and I intend to make the most of it, if my phone ever gets to update to that version.
Now, what are the potential side-effects? Well, legitimate app makers will want to explain why they need certain permissions, but will need to write their apps to deal with the situation if they are running without them. Less scrupulous app makers will actively ensure their apps don't work at all unless all of their sleazy permissions are enabled. Don't expect to disable the ability of the Facebook app to read your contacts and messages and still have it work. They don't want to lose that permission and the juicy, juicy data that makes their money in the process, so the app will simply refuse to operate if those permissions are denied.
Mokalus of Borg
PS - Probably.
PPS - It depends how many people actually try to turn the permissions off and how many kick up a stink about it.