Yes, more of a missing editor feature, indeed. I can't think of any editor that has properly-working & stress-free texture lock. In Quest, I would never use it, because it screwed up the originally clean offset (not noticable after compiling but awkward for further in-editor use), and it wouldn't work with rotation at all. In Radiant, locking textures for rotation works, but it resorts to using floats for offset and angles which qbsp can't interpret and thus rounds, so it still requires manual work.
Keep in mind that WC3.3 isn't meant for Quake mapping originally (and, to a lesser extent, neither is modern Quark). I think people only use it because they like how WC works, but prefer whatever technical improvements 3.3 has when it comes to certain features that are still relevant for Quake mapping (=nothing map format-specific).