A player brought up truenamer, of which I have an idea to fix the class' dc problems.

Truename dc based on 15 plus CR or HD which ever one is higher [plus 1-5 for boss fights] and the roll it's self is Charisma modifier plus level, instead of a class skill.
Know the target's truename, plus 4 to the rolls against said creature.

This way a player can't optimize their Truenamer skill, as well, and it is possible for a flubbed word or two.

Example: 5th level Player has 18 in charisma, and is facing an unknown Minotaur. The dc would be 21, meaning the player needs to roll a 12 or higher on every attempt.

Just wondering if you think this would work for, or is it only in my head that it does.