We just checked out today, spent 7 nights in the world. The good news, crowds were lower than we normally have seen during this time (we go each year). You notice it most at Epcot (we did a 7:30 dinner in World show case, got in line for FEA and ride in about 30 minutes), easy to walk through the park, etc.
Fair warning, it rained ALOT more this trip...kept temps manageable and crowds lower, but TT was often closed, etc.
Magic Kingdom is just nuts with the 10 pm close. It felt as crowded as New Year's Day week did for us this year. hEA is a crowded mess, and although a neat show, IMO you lose the magic with the crowded view areas. Leaving the park is a madness and expect it to take very long to get a bus or monorail out from the time HEA ends until 10:30. We attempted to park hopti AK after HEA (watching it from the train station and leaving right away), Disney even brought in charter buses to help, but it took over an hour before we got to AK.
If you do MK on the evening EMH night do not even attempt to go in before 7:30 and do not plan to watch fireworks, just head back and do attractions like people mover (and yes expect wall to walk people and a 15 minute wait for people mover), but once the fireworks start, you can ride a lot--we ride tons, most with little wait! We closed the park that night, and it was the only time MK was not a madhouse (note we did not attempt rope drop this trip).
