I saw them open up with Master's Apprentices. It was pretty badass.
It's kind of sad, in one tour Opeth went from "See every time no matter what" to "Maybe if the set is good and even then...". If they play a set like this one: http://metalsetlists.com/showthread.php?t=21817
I'll go no doubt but if it's Heritage pt. 3 I'm keeping my money.