Simple question: Should a new wall be primed before applying wallpaper? Or can I just do it over finished drywall.
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.
Yes, you should use wall paper primer on drywall, because otherwise the drywall will suck up too much of the glue and the wall paper will not stick well, and you will have to use more glue. A good wall paper primer for drywall is simply diluted wall paper glue. The package of good wall paper glue should instruct you on how to use it as a primer.
I gave an up vote on "Yes, please prime", because I too have spent many hours scraping wallpaper off unprimed drywall. American tastes went though some tough times in the 60's and 70's with wallpaper. (Remember the DIAGONAL PHASE?). If your tastes ever change, it will be much easier to get off. Drywall primer also helps with positioning and keeping the seams glued down instead of curling up.