The whole idea about MMORPGs is to live out the character you create. Just having skills in attacking and casting spells is boring. You really need skills for movement aswell; athletics, acrobatics, and such. It would make the game much more fun.
Seriously, going up to someone with a high skill in acrobatics and running while you haven\'t invested in those skills isn\'t any less fair then going up to someone with high skill in weapons and armor when you\'ve invested in something else. We need to keep the balance, to be sure, but just because you haven\'t the same abilities when it comes to athletics or acrobatics doesn\'t mean you haven\'t invested your skill points somewhere else which could just as easily be of use to you. That\'s just the reason why skills exist; to make your game play different than other people\'s, playing your own way, right? Doesn\'t mean any one thing is more unfair. Just means it\'s a different choice of skills.
Basically, If players want to invest in skills which make them more agile, then they sure as shootin\' should be able to do it.
EDIT: It\'s really not as unrealistic as you\'d imagen; it might not be true in the real world that you can jump so high, but you have to consider that some of the races here are modeled after creatures that are widely known for their jumping. Some lizards jump 10 times their height, and cats can jump quite high too, compared to humans. And jumping high is often featured in 3D games, and most of the time people don\'t go and say \"omg tat\'s imposibalerzzz!\" (EDIT NOTE: I just want to make sure you understand, I\'m not mocking you, I just always quote that way cauz I\'m weird) or whatever; it just makes the game more fun. And I don\'t think whether or not it\'s online should really matter much. It\'s not like everyone will be jumping roofs, as I clearly stated before.
The thing is, I really don\'t think that it will be too much of a problem. How about you just consider adding it, and if it\'s really a problem you can take it out? It\'s not like it\'s that hard to program in, ya know. I\'m still convinced that it would be a feature which would add a lot to the game.