I'm all for jumping as long as it serves a purpose. Jumping for the sake of jumping is stupid and lazy, might as well not have it at all at that point.

If it serves a purpose such as terrain navigation, avoiding obstacles or even navigating platforming segments I'm all for it. IF they added things like that then I could see jumping adding some more fun to the otherwise boring task of moving from point A to point B. Not saying they will but if they did. The only way to really answer how it would make the game more fun is to speculate situations in which it would.

If it was just there for the sake of allowing you to jump with no purpose I would of course be against it. Why add a mechanic to the game that serves no real gameplay purpose? At that point you would just have people bunny hopping around for no reason.

The one restriction I would like to see on jumping though is that it cannot take priority over any battle action. The reason for this is because in Aion people liked to use jumping as an exploit to cancel battle animations on Ranger and that was adopted as the only way to play the class for a while. It was pretty obnoxious and I'd like to not see that happen here.