The idea of allowing users to control what individual permissions they have is good in theory, very hard in practice. It faces two main challenges that I can think of:
1) There are UI issues that have been raised elsewhere in this thread - mainly, that users get confused when shown a set of complex options. Having watched usability studies where users are given a lot of relatively complex options, I'd suspect that a model where users have to pick among the permissions to give an app is going to fail massively (ie, user turns on everything without actually understanding anything, turns off everything by default or just cancels out of the app install altogether.) A model where apps request permissions right when it's needed will be annoying users with all the dialogs needed.
2) Some apps don't work if they don't get all the permissions they need (imagine an address book app for an email program - if you don't get email address it just doesn't work.) Adding a lot of conditionals to change how your app works based on what permissions they get can be expensive and adds a lot of unnecessary test cases.
In my opinion, Facebook's decision give more granular permissions, but to make it an all or nothing proposition allows them to protect their users by removing spammy/malicious apps, and simplifies the applications built on their platform . This puts responsibility on them to actively remove malicious applications, and on developers to pick only the permissions they need. Given that users tend to make bad decisions given a set of complex options that they don't understand, it seems like they made a rational choice. AppStores on the various phone platforms have a similar decision to make as to how to best protect users from apps, and there isn't consensus as to the best model in that arena either.
They do need to step up their activity to remove malicious apps in light of giving regular applications this option.
1) There are UI issues that have been raised elsewhere in this thread - mainly, that users get confused when shown a set of complex options. Having watched usability studies where users are given a lot of relatively complex options, I'd suspect that a model where users have to pick among the permissions to give an app is going to fail massively (ie, user turns on everything without actually understanding anything, turns off everything by default or just cancels out of the app install altogether.) A model where apps request permissions right when it's needed will be annoying users with all the dialogs needed.
2) Some apps don't work if they don't get all the permissions they need (imagine an address book app for an email program - if you don't get email address it just doesn't work.) Adding a lot of conditionals to change how your app works based on what permissions they get can be expensive and adds a lot of unnecessary test cases.
In my opinion, Facebook's decision give more granular permissions, but to make it an all or nothing proposition allows them to protect their users by removing spammy/malicious apps, and simplifies the applications built on their platform . This puts responsibility on them to actively remove malicious applications, and on developers to pick only the permissions they need. Given that users tend to make bad decisions given a set of complex options that they don't understand, it seems like they made a rational choice. AppStores on the various phone platforms have a similar decision to make as to how to best protect users from apps, and there isn't consensus as to the best model in that arena either.
They do need to step up their activity to remove malicious apps in light of giving regular applications this option.