That's not about old vs current - you are always locked in place at the very beginning of the dungeon. When the MSQ dungeon cutscenes were skippable, they were the same - you were locked in place during the intro cutscene but no others. They don't seem to be able to re-apply that lock mid-dungeon, or it would be an obvious solution.
I don't see what this has to do with "SE not trusting us" though. How would locking us in place be any different?
If anything I think it's what they could do within their system. They can force unskippable cutscenes and auto-scrolling text, as both functions already existed elsewhere in the game, but probably can't force locking in place.