Well, I think that could affect the exclusive titles. Especially PVP ones. What stops them from recreating them.
Make it so they can't re-create the Event reward titles.
That would also mean disabling capital L's. And I have seen people finding their ways around with making some sort of a space before the word that counts as a letter.
Could make it so Agatio or whoever makes the titles would have to approve it before allowing someone to use it.
Custom titles, unlike faction icons, require server reboot to add and since we have main patches around once a month, the waiting time would be unacceptably long... Of course I could do reboots more often, but that would annoy players and I do prefer doing them once patch is fully ready to save my time.
Patience is bitter, but its fruit is sweet.