as someone who plays a lot of jax I dont see anything wrong with this. would help jax players ensure their stun and allow players to walk out of the range of the stun as well. it would allow for counterplay for both sides. the original poster is right, currently it extends slightly past the visuals.
rather than a range indicator they can just update the visuals to match the range. that would be preferred. like they did with lux E. Lux E used to be cancerous in lane as you didn't know how close to the E you could get. once they got star guardian lux visuals they fixed the visuals on all skins and bam now you can see exactly where its range is.