See that's the thing.. Jumping is pretty well useless except in FPS type games where aiming is very important. I mean like headshots versus backside shots. Of course personally for an MMO I don't think that would work too well. Essentially so long as we can climb on or over things rather than running along and getting stuck on a rock.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson