That would be actually interesting, since a good bunch of players always try to climb everywhere, but nearly impossible to do so. Besides the fact they have higher priorities, ladders would require new animations for each race and some extra work with hitboxes, which in turn could lead to new bugs being added - some of them of the good kind, like the glorious emote glitch from 2.0, some of the bad kind - which would bring an unknown amount of time to readjust the game engine.

Not really feasible, but it doesn't hurt to dream.