We go to WDW the last week of March every year, which this year turns out to include Easter and the week following. The weather is usually lovely - not too hot, but warm enough to swim in the heated resort pools. If we're going to be at the parks late, we'll usually take sweatshirts or jackets. It's always crowded at that time, and exceptionally so when Easter falls in that time period. But if you plan right you can deal with the crowds, and the parks are open for lots of hours, with extra showings of Fantasmic and Spectro on many nights. I'd prefer to go at a less crowded time, but this is when we have Spring Break, and it is definitely manageable.