
I'm also not sure, as I have not personally coded for an MMORPG, but I do know that jumping lead to a whole host of problems in WoW. Granted a lot were pvp but they were easily adapted for pve as well.
Being able to jump onto ledges and glitch bosses to get "Watch him die" achievement. Jumping any sort of stun in pvp completely negated the stun, locked the person in animation and let you run pretty far away. Wall climbing was another major issue they cracked down on...sadly...as I loved to wall climb into Hyjal.
It could be that a lot of the rocks, and other things are actually just painted on and do not actually have collision detection and you would just pass through them into oblivion (this happened a lot to me in WoW). This can be solved with creating invisible walls everywhere, but that also can result in clipping issues if a person is hugging a wall to avoid aggro.
I'm not sure what the seismic shock animation looks like, do you actually jump or is it a flip of some sort? They could have just been lazy and not wanted to code a jump animation. They did use a lot of motion capture for the game, but perhaps asians just don't got no ups?
Edit:Nifty thing I found when looking for how high an average person can jump:
<!-- m --><a class="postlink" href="http://www.exrx.net/Calculators/VerticalJump.html">http://www.exrx.net/Calculators/VerticalJump.html</a><!-- m -->
Being able to jump onto ledges and glitch bosses to get "Watch him die" achievement. Jumping any sort of stun in pvp completely negated the stun, locked the person in animation and let you run pretty far away. Wall climbing was another major issue they cracked down on...sadly...as I loved to wall climb into Hyjal.
It could be that a lot of the rocks, and other things are actually just painted on and do not actually have collision detection and you would just pass through them into oblivion (this happened a lot to me in WoW). This can be solved with creating invisible walls everywhere, but that also can result in clipping issues if a person is hugging a wall to avoid aggro.
I'm not sure what the seismic shock animation looks like, do you actually jump or is it a flip of some sort? They could have just been lazy and not wanted to code a jump animation. They did use a lot of motion capture for the game, but perhaps asians just don't got no ups?

Edit:Nifty thing I found when looking for how high an average person can jump:
<!-- m --><a class="postlink" href="http://www.exrx.net/Calculators/VerticalJump.html">http://www.exrx.net/Calculators/VerticalJump.html</a><!-- m -->