However, a jump feature would certainly have uses, like getting over that small cliff that's slightly too big to walk over.
I am honestly curious where you're referring to. After they tweaked the terrain collision a long while back, I haven't found any place I couldn't run over that also didn't come up to at least my knees or waist. Remember that the lines on the minimap coincide with the impassable terrain--if you're not crossing a line on the map, you can walk over it.

Basically, I keep seeing this (quite old alpha-era) argument, and no examples to back it up, and I haven't experienced it at all from, gosh, open beta onwards.