charliepreed: Bethesda's current engine is the new id tech, the engine that powers Rage. So that logic is now fail.
Curunauth: The article is recent, and ID Tech 4 may not have ladder handling capability in the core AI components. Alternately, a RPG-style game might use the render engine and replace the AI portion entirely with their own code. The article notes that the issue isn't rendering and navigation support, but AI pathing -- and very very few games have AI that handles general-case ladders well if at all. In RPGs, pathing failure can be game-breaking rather than just annoying, so it makes sense to just steer clear and design spiral staircases or other compact, non-ladder methods of ascent.
Id tech should have ladder path-finding. It did in older versions, would be strange to take it out. But your right we don't know. I'm not sure it's game breaking though.,