Jumping puzzles are a good example, and doesn't matter if a class or faction offers some back-up to handle it, that is part of the world (And I've seen enough Venthyr members, and Demon Hunters fail basic jumping puzzles before). That is as well, something needed in the world. As said in the post (you might have read by now), the core needs more. And yes, the developers are most likely worried about the engine as it doesn't have a section that permits the player to control the world and would need a module upgrade, overhaul - or even a new one.