I really think Funcom should look at NPC/creature climbing for those that can do so, but be subject to all the constraints that players are, such as stamina, armor encumbrance, and falling damage if knocked off. Furthermore, I also think that winged creatures such as the children of Jhil should be able to actually fly.
I think this would solve a lot of problems such as bases that would normally be unreachable to purges and would make much more sense that undead suddenly appearing in the middle of your base.