I think the only songs that should be on the permanent concert setlist are:
Streets
Bad
Oh, and I guess Sunday Bloody Sunday too. As long as the state of the world requires U2 to keep singing that song, it cannot be dropped from the setlist without violating some unwritten law of nature.
Other than that, please, please bring back some of the lesser played songs. Out of Control from the Elevation tour was brilliant. I would love to see The Electric Co on the next tour. Hawkmoon 269 would be great too.
But please, for the love of all that is holy, drop WOWY and Bullet! We've heard enough of those songs already.