If the dip affected everyone equally it wouldn't be that bad, as most of the saturation found above the 4.8 would be leveraged... However these suggestions will be rated, in average, as greater as the overall empathy and knowledge users have regarding the kind of app in question. For instance, regarding my app Tabata Trainer (which went from solid 4.57 in December 9th to 4.21 at the time of this post), how many persons identify with the word "Tabata"? Most of them will never give a 5. If someone creates a game with a very similar name to a widely known and adorable game, then people will probably rate the suggestion highly. This kind of stuff will just lead apps to be rated unequally... and bad (really bad) apps will raise their ratings, which is shameful.

Not until the users view of those ratings rescale too.