Being able to download again for free kind of misses the point of the question.
Originally Posted by Snowman
First, that doesn't help much if either the developer or Apple decides to pull the game. For example, being able to download again for free wouldn't help you much if you deleted Stoneloops of Jurasica.
Second, my question was more concerned with the developer adding things in an update. For example, say you have a game with 50 levels and you've finished all 50 levels. If you delete the game from your iPhone and the developer releases an update with 20 new levels, you'd have to start from scratch at level 1 unless you left the previously completed game on your iPhone.