This is what we found in mid-November when the parks were not hugely crowded like they will be near Christmas: the paper passes are still available at the parks; however, with onset of FP+, what we found is that for RnR, Tower, Soarin and Test Track, the paper fastpasses ran out for the day by 11:00 a.m., which is during a time of year when they were previously still readily available late in the afternoon.
What we also found is that they still have a long way to go in figuring out how many FP+ should be allowed for any particular time based on estimated probable use. For example, when we used FP+ for Toy Story, the stand-by line was 40 minutes; it took us 30 minutes to get from the entry at the fastpass line to the ride; similar experience at Soarin' when stand-by was just under an hour and fastpass lane took almost 40 minutes.