That's my question....
Based on (a lot) of my research, it seems that lines are never bad with express pass. The days I had planned were in the 7/8 range, and with ExP, TP was showing 5-10 min waits. Of course the the two "big" Harry Potter rides are not included in the ExP, so there will be waits, regardless. But I've read that if you use the EE, neither is too bad.
Express pass lines rarely exceed 15 mins. The exception is DIspicable Me ride which can hit 40 mins for exp as its not a continuous loader. A very general rule of thumb is express pass wait is a third of standby or less. As Dis Me hits 2hr plus for standby ride it as early as poss.
Thank you, this was very helpful! They must limit the passes.