I think people are reading way too much into the interview. Just because Edge says only two songs will be different from night to night doesn't mean it will be EXACTLY two. Same with the amount of songs from NLOTH.
How I see it, the setlists will be similar in style to that of the Vertigo Tour. Think of all the "new" songs we got on the last tour: Gloria, The Electric Co, The Ocean, An Cat Dubh, Wild Horses, Miss Sarajevo, The First Time, Zoo Station, etc. All of these were songs we never thought they'd play again, but they did. And some of the songs, like Zoo Station, were played pretty consistently throughout the tour.
Now, imagine something similar, but instead of the songs mentioned above, it will be a completely new group of older songs. Some will come and go, but some will have an important place in the set and will be played virtually every night. And while some shows on the Vertigo Tour only did see a change of two songs from night to night, that was not true of every setlist on the tour.
U2 have very choreographed shows. They always have and they always will. People who expect twenty different songs every night are following the wrong band. The last tour had some of U2's most diverse setlists ever, and as long as that continues this tour, I'll be happy.