The problem with jumping is the vast differences in heights of the races. nobody can jump higher than their head, most not higher than their waist, so how would you account for terrain that a elvaan could jump over, but a tarutaru could not? Also nobody can jump as high wearing platemail as they can naked. This would "ruin the immersion" as you all like to claim so much.
in ffxi the tarutaru ran just as fast as the elvaan and mithra, why not have the lalafell jump as tall as the rest of the races and just put it off to small but powerful legs? vise-versa, jumping would be more immersion than no jumping, or mostly flattened maps
as for the armor, they could just implement a system that makes it harder to move because of weight, like a plate of mail would make your jumps shorter, and your walking slow, swimming more difficult, etc
fallout 3, off the top of my head, does this, depending on what you're wearing/carring affects your movement, and if you have certain things equipped you can't jump
Edited, Nov 2nd 2009 9:56pm by TheFatHousecat