How bad would adding Jump ruin the game balance?

Let’s say, hypothetically speaking, Hinterland decided to say “you know what, there’s a jump button now”. So you can hop fences, and free yourself when you get stuck in geometry (let’s face it the game is still very rough around every edge in that regard), and there’s probably at least one cliff wall you can scale skyrim style. Let’s say you can’t jump while encumbered or low on stamina, and you can’t jump onto the roof of a car, and you can’t jump on thin ice (or if you do you just fall in when you land). Are there any oversights that would allow for exploits and glitches so horrendous it would actively be detrimental to the gameplay as a whole?

UPDATE- Alternative suggestion:

You know how you could jump in Dark Souls and on, but not in Demon’s Souls? But Demon’s Souls had a feature where if you walked into climbable ledges it would do that automatically? Hinterland already has a context-sensitive climb mechanic build into the game, so theoretically they could add a context sensitive jump command only usable at specifically coded locations such as fences, docks, and certain hills. Would this then be a fair compromise over a jump usable wherever?