I agree that race differentiation has been lost with every race having the same maximum for every stat, and often not much initial stat difference. You could make each race have a different maximum for each stats, maybe between 4 and 7, so that each race has a purpose, as right now there's not much point using some of the smaller races. This might also give a purpose for humans, if they have no stat maxing at 7, but multiple at 6, so they can be great late game.
In addition,there could be certain classes or events that increase one's maximum stat. Higher tier classes would have more of an appeal, and events like completing a character's unique quest, getting married, having children could all increase maximum potentials.