BTW, the physics engine was changed more than once - and one of the major changes was when we went through the U5 combat nerfdate (~may 13, 2010) where they completely ganked EQs doublestrike and offhand proc mechanic and schlepped it into this game. Thats when the collision physics began to fail. Update 6 was red fens, and we were already able to walk through walls to get to the red fens slayer area before U6 went live (~aug 17, 2010).
And none of that is even close to relevant right now, since the current physics engine is a completely different one. The Red Fens "Hole" was actually in the game code not the physics engine.