We were there the first week of May this year and it was crowded even though nothing was going on. It may have seemed more crowded than it really was because so many rides were closed (Pirates, Small World, Indiana Jones, Alice, Nemo, & GRR).
The only thing that may make it "super crowded" is if people show up early for the Tinkerbell Marathon weekend May 7-10, which a lot of them probably will.
I think so many people are taking their kids off of school trying to find a "slow week" that slow weeks aren't so slow anymore.