Since it is positive energy, you can still use the ability as a touch attack against undead if you wish. Maybe not as great an effect as turning them, but then turning them can't be used to heal. I will leave it up to you as to which ability you prefer. I just thought I would offer it since having healing is often difficult at low levels.
(As I said, sounds good! After all, Defenders are the turners of the order, diviners are.)