Good move. As convenient as it makes rating an app, it is definitely skewed towards low ratings as people deleting apps most likely don't like the app.
You are skewing logic here...
If people delete the app as you say most likely don't like it, so they should be able to give it a low rating. Why is this skewing towards low ratings? The apps that are liked and not deleted, don't get bad ratings, but the ones that are deleted, get the bad ratings. If these apps were any good, they would not be deleted and they wouldn't be getting bad ratings? So, ultimately the good apps that are not deleted get the better grades, and those that do get deleted the worst.
I think this not only does not skew ratings, it rectifies them.
Moronic reporting by macrumors too, who take this biased view without any criticism. This does decrease overall ratings, but it doesn't skew them in any way. The good apps don't get deleted and don't get the bad rating, simple as that, the bad ones do, and deservedly so.
This is a bad move, because now, an app can be very unsatisfactory and it can be deleted by many iphone users, yet none of them will be prompted to rate it, and so give the negative feedback back to the community. Only if the user is really motivated, and the app is atrocious will they explicitly go to the app store and rate it...
Bad, Bad move, now all those third rate apps that we delete from our phones won't get a just low rating, and they will escape for some other poor schmuck to download unbeknownst to them.