A rope climb has nothing to do with balance. Pulling yourself up a ledge has nothing to do with balance. You seem to be solely picturing three/four point rock climbing for all types of climbing.
And frankly, other than the bare minimum balance of not throwing only part of your body in a direction, I don't see what balance has to do with jumping, or why that can't be handled well enough with a 10 dex.
And what the heck does agile athletics mean in game terms? Or are you just saying they would be good at a single skill, like they already are?