I am not going to defend disney because they do not need any defense. Everyday business make decisions based on concrete and not so concrete data that affects our lives. Disney has done nothing more than make these kinds of adjustments.
March is not value season therefore you will not get value prices. In Florida, March is prime time for people to come and visit. The vacation season, if you will, starts a week or so before the Daytona 500 which is direcctly followed by Bike Week in Daytona. Just as the motorcycle enthusiasts begin to leave the area, spring break season kicks in bringing college and highschool students and their parents to Florida. Spring Break continues through the week following Easter Sunday which this year is April 20. That means the Spring break season which is usually compacted into 3 to 4 weeks will extend almost two months. If you notice near Easter Sunday the hours do extend later into the evening.
The net effect of this extended spring break season is the parks will be less busy in march and early April that what would be considered normal. Therefore the hours were adjusted to reflect the fact that a guest will need to spend less time in the parks in order to experience all the rides and attractions. I know many people think this is wrong but you have to keep it in perspective. When purchasing any other form of entertainment you dont get unlimited refills. If you go to a broadway play, your admission prices doesnt entitle you to unlimited performances. You watch the play once and depart.
On the average day at the Magic Kingdom, like the ones they are apparently expecting in March, you can cover a lot of things not just once but twice or more in the 9 hours the park will be open. The best part of course is that after that you can head over to EPCOT, watch an awesome fireworks show and eat popcorn with your family at no additional charge.
That to me doesn't sound like a bad deal at all. However, if you still want longer hours in the park, then I suggest you postpone your Disney trip until mid July. Not only will the hours in the parks be extended but you will also be able to enjoy only part of the attractions they have to offer no more than one time each day with 40 or 50 thousand of your closest friends.