If they implemented this, it would be very cool!
Put simply - as your demigod levels up, there will be visual changes to make him look more powerful/different!
E.g. Demigods will look as they do at present, from levels 1-10. However, upon reaching level 10, they look slightly different (e.g. more armour plating, or the torchbearer gets a sicker looking torch)...and upon lvl 25, will look even more deadlier!
Visual changes would occur at:
lvl 10 -minor changes e.g. a slightly different looking crossbow for regulas, or bigger fangs for unclean beast
lvl 20 -slightly more visual change - perhaps a change in the apparel side of things e.g. a more elaborate/ornate breastplate for regulas (but this shouldn't conflict with the 'minor' change made at lvl 10 - this should still be visible.
lvl 25 -entirely new appearance (e.g. a totally epic looking crossbow for regulas, even more ornate breastplate).
I think this would be awesome!