Well, for what its worth - I'm not happy with the MK hours either.
But, I can understand closing MK early for Grad Night and don't have a problem with it.
However, why don't they alternate park hours between MK and the studios - the studios are open til 830/900 during the first two weeks of May i.e. have the studios open til 9 on Fri, Sat, Sun, Mon and MK open til 7 and then on Tues, Wed, Thurs have MK open til 9 with fireworks/spectro and the studios close early at 6 or 7.
At least that way everyone gets to enjoy their favorite park in the evening which ever it may be - and if they can't do that - throw in an Enight or two each week at the MK.
At least that is a compromise and seems to be a win win situation.