Crowds on a week-end in the summer is bound to be bad.
I'd mentally prepare for the absolute worst, and then be thrilled if it's actually better than that. Have a strategy mapped out, make sure you're familiar with FastPass, then go and have a good time!!
busy, but not bearable..maybe its just me but I dont see how any day at WDW could be unbearable. lol..ive been there at the same time, just dont rush, and take it slow. It'll be pretty hot.