Here's some of the things I'd look at to assess that time:
- Review Spring Breaks times for 2006 - we find those affect crowds.
- See when Disney's "Flower Power" starts - a spike at Epcot and you might yourself enjoy incorporating some of those unique "to dos" into your itinerary.
- Watch Disney operating hours and their firework times: If you have longer hours and fireworks nightly at MK and 2 Fntsmcs at MGM - then I'd say their expecting big crowds, if you see shorter operating hours and less fireworks at MK and MGM, that usually indicates an expectation of "lesser" crowds (which then Disney proceeds to imagineer them into the parks you decide to go to that day. LOL).
Some additional good things about going at that time of year:
1. Yes, weather is warming up - not the heat of July/Aug but you'll feel the difference coming from a "winter" zone. Incorporate fun time at the pool.
2. If it's the Flower Power they'll have 60s live bands at the American Pavilion at Epcot - there'll be short seminars, and other interesting "to dos" you get to add to your trip.
3. Ah yes, and the flowers!!! Be sure to walk that rose path near Imagination - the scent is wonderful.
4. Also, at this time of year it's fun going to TL and BB - esp. if FL kids are back in school the week following (you might want to check FL kids' vacation times then - otherwise those water parks might be esp. busy).
Have fun planning your Spring Vaca.