This seems to me to be indicative of a problem with the Facebook apps platform. They are using significant resources to try to combat spam, but the spam is posted through the mechanisms provided by the platform.
What I'm suggesting is that the Facebook apps platform is fundamentally making it easy to post spam so they have to fight it afterward.
Would a better approach be to shore up the platform so that apps are simply unable to generate spam? For example, currently a user can only Allow or Disallow an app. They cannot Allow or Disallow certain permissions. I should be able to use an app while denying it the possibility to post to my wall or my friends walls.
It seems like it's the wrong approach to try to stop the spam by banning apps rather than fundamentally changing the way apps can access person sites and information and make generating spam incredibly difficult.
Yep, that's always been the problem as far as i can remember. The same thing happened with facebook requests, notifications, profile boxes. If something can be spammed, it will be spammed. However your solution means that apps will have 0 exposure, as the stream is the last channel that facebook has left open. A better solution would be to bring back notifications, which are less intrusive and feel temporary. They might reinstate the quotas they used to have on the number of notifications per app per day they had based on spam feedback.