Originally Posted by
Strmchsr
Crowds are definitely lighter than those times you mentioned. It's not empty because no time of the year is any more, but comparatively they're light. Can you do more? Well, somewhat. Yes, crowds are lower, but as a result the parks often close earlier so that knocks off some park time if you're one that likes to close the parks out. For instance, DAK will close at 7 during May, but 5 during September. DHS might close at 9 or 10 in May but 7 in September and so on. And, as mentioned previously, there are the MNSSHP nights at MK that closes MK down at 7 several nights a week.
As for the DDP - that's the one big drawback to September. Everyone now expects the "free" DDP in September which means restaurants are NUTS and ADRs can be very hard to get. The park itself doesn't feel crowded but the restaurants can feel like peak season because everyone is on the DDP.