Maybe it's good idea to give access to heretism for other races (for example, 'dark' dunadans or night elves) paladins so they would be able to get access to it through certain 'initiation' (like corrupted maia)?
For example:
- you create paladin/dunadan
- at lvl 10 you could meet an elf Gildor ( http://tolkiengateway.net/wiki/Gildor ).. If you would kill him - you would become 'heretic' and would have access to this school (and ban for holy ones)
It's fits to lore quite good.
