I myself am currently attempting (and succeeding by the look of things) to set up up a PFS night at my local gaming club, and this very issue has been raised.
At present there are 42 scenarios available for purchase, with 2 scenarios released at the end of each month save for two notable exceptions where 4 are promised.
Obviously this won't impact the members of our club for easily over a year or so, but my thought is that the great majority of store organised play will be based weekly. Surely this means that at some point you're going to run into a brick wall with a lack of content? Especially if replays aren't allowed.
My fellow gamers garner a huge sense of accomplishment from character advancement, and I really don't see them smiling benignly and accepting the idea of playing through a previous scenario for no reward. (No matter how fun it may be)
Frankly, I could be taking them through one of the excellent Pathfinder Modules instead to fill in the gap, but I feel that this would also be missing the point of organised play.
I am in favour of replays, but I can't provide much input yet on the format this should take as I'm still getting this thing off the ground.
Common sense suggests that a limited reward should be offered for a replay, along with the prerequisite 1xp.
But I am also leaning towards the idea that this may only be accomplished with a character of a differing faction, but that throws into question whether limiting treasure and PA is fair or whether or not it'll 'stunt' that particular PCs progression.
Not to mention that you could also liken this to GM rewards, where if the players can replay for advancement, why couldn't a GM rerun a scenario to give the benefit to another of his characters?
A GM who does little more than run games, but periodically wants to play a meaningful game is not only going to find himself somewhat spent for choice, but also realise that his character wealth and PA spending cap/perks are well below the average of most of the other players around his table.
Just my thoughts, of course.