Try powdering the clay/putty with talk or cornstarch. Roll it out flat first, then thoroughly powder the surface, then go over it with the (dry) texture roller.
I feel like applying release to the roller creates problems with the release getting wiped off in the process of rolling. Applying it to the clay/putty instead ensures that the point of contact is always evenly covered.
Plus water doesn't really "stick" to acrylic, so it's easy to end up with all kinds of little spots where droplets have rolled away or whatever before it even has a chance to touch the clay. Oil or Vaseline would be better, but then you have to de-grease the clay/putty afterward before you can add anything more to it, which usually means having to harden it first (or wait for it to harden). With powder you can just blow off the excess and give it a spritz of water and you're ready for the next layer right then and there.
Doesn't seem odd to me that GS wouldn't pick up many crisp edges from the roller. That's not the GS being old, that's just how GS is. Makes sculpting organic shapes easier, 'cause rounded shapes/surfaces form naturally between tool marks, but it's also the reason why lots of sculptors switch to other materials when they have to do hard surface bits.