I've owned a bunch of properties over the years including three rental properties that were at least 70 years old -- lots of abused walls. I've always repaired pockmarked walls the hard way: spackle/sand, spackle/sand until pleasing to the eye. I repair cracks using fiberglass tape and epoxy and/or spackle. I haven't used Roll-A-Tex but it just doesn't look like the best way to go. Consider using "wall liner" that is applied like wallpaper. It bridges imperfections, turns hard (like plaster) after application, and it can be painted or papered. You could surface an entire wall with liner or portions. The sheet edges would need to be feather edged with spackle, of course. I've seen wall liner in Home Depot and Lowes plus it's readily available on-line.