I went in the Easter holidays this year and it was lovely, and I think it would be even better next year as Easter is later so it should be warmer! The queues were really short so we managed to do everything at least once (we went some rides 10 times over 5 days!) and we had a brilliant time. There aren't as many characters around as in the summer, but there's still quite a few, especially in Fantasyland. We found that Wednesday was busier than the other days but it was still manageable.
As you get closer to the Easter weekend, it tends to get much busier so keep that in mind!