I remember how in Aura Kingdom, you just unlocked titles as you progressed and simply changed to a better one as soon as you had one... I like my title, and I very much want to keep it and not change to another one for stats. Some active buff that doesn't change anything about your appearence okay, some system where some achievemts unlock buffs you can pick between, and they give you a boost to something related to it, examples having been mentioned already but don't add obvious benefits to titles.