Last April's ABD took place the middle of the month, but was not Easter Week. However, since it was a traditional Spring Break week, the crowds were big. The fastpasses were very helpful, we received five per person on day four (
Disneyland) and day five (California Adventure). Speaking for myself, I found it to be enjoyable even though it was very crowded. We were back doored on so many attractions (I don't want to say which ones because I don't want to give anything away

), that in my free time I was able to easily pick and choose what I wanted to use my fastpasses on because we had already seen so much as a group.
I found that when I was on my own time and the crowds got to be too much, I would leave and go back Grand Californian to relax (just sitting in the lobby is a great way to decompress) or go over to Downtown Disney to have a snack or a meal before going back into the parks.
I hope this helps!
Jason