My suggestion is to have the Improved Turning enhancements modify all turn based actions.

For example:

Improved Turning:

- Increases your level for the purposes of turning undead by 1.
- Increases Divine Might duration by 1 minute
- Increases Divine Light damage by 10%

- Increases Divine Righteousness duration or hate (Paladin)
- Increases Divine Cleansing Duration (Cleric)
- Increases Divine Healing healing by 10% (Cleric)
- Increases Spell points given by Divine Vitality by 10% (Cleric)

This could be for the feat and the enhancements.