This is a very poorly thought out plan. When you delete an app you’re asked to rate the app, where a dialog is popped that gives the option of selecting between 0 and 5 stars.
At first thought, there will be lots more app ratings and this will help Apple kull (my favorite word this week) poor applications. On second thought, why would you give a good rating to an app you wish to remove? And how about an app you never remove? There will be many bad ratings applied to apps, without getting an equal response from those who like the app and keep it… The users who love the app will never be prompted for their rating.