If you are not going to take advantage of the EMH, then I would go to a different park. I agree with what was said before, in that I don't believe that the parks that will be open late will be crowded in the morning. I am sure they won't begin getting crwded until later on in the afternoon. Again, if you don't plan on taking advantage of this, I would avoid these parks later on in the day.
In my opinion, the late evening deal is going to require more dodging of crowds - more park hoping inotherwords; however, the late evening will be nice every so often on a trip for us to hop on the rides that are often over crowded with little ones wanting to ride or just to look at the beautiful lights at night!