Priming new wall before wallpaper
Please yes!  I am literally 90% done doing a complete remodel of my house.  Other than the aluminum wiring that I have replaced the #1 biggest stupid thing I have dealt with is the 20 (no exaggeration) different types of wallpaper put on the house in 1967 during the custom build.  Out of the 20 only 3-4 types (2 specific rooms) had primer.  Those two rooms took like 20 mins a piece to get the wallpaper down with very little repairing.  

In the rooms without primer, I often looked back and thought it might have been easier to rip drywall out and start over - it was that bad.  So please prime first.  If not for you in a few years, for the next home owners.