We're re-doing our kitchen that was built in 1980. The old countertops were cement & tile with the tile continuing into the backsplash on the wall.
We've removed the old counters, backsplash, and cabinets which has given us a better look at the current drywall situation:
As you can see there is still a significant amount of binding agent left over from where the tile backsplash was (it seems like cement but idk). Overall though, it seems like the drywall is in decent shape so I don't think we need all out replacement.
We are getting new cabinets and countertops and plan on doing another tile backsplash that has a similar (but probably not identical) footprint where the previous backsplash was.
Based on my research, we should be removing the old material in order to make sure the new tiles can be installed flush and bind successfully. My first instinct was to use our handheld orbital sander to try to remove it. Is there a better way?