How is your Draenai, lore wise, not being corrupted by the Fel or Shadow, morphed into a broken?
How would a lightbound Draenai be able to control the Fel, would they go to summon a demon and it just instantly incinerate in the light?
These are just a few of the questions that quickly come to mind when dealing with this.
It’s the reason we don’t add halforc halfpotatos to be a customization option, blizz just takes the choice away from them so that their games story and character races can have some structure and sense of culture and differences amongst them.