Not a lot of PrCs advance turning and allow full progression.
If I were to try to salvage this ability, I would simply make it equal to caster level and usable three times per day. Death effects with no save are pretty useful.
If most other domain powers were linked to cleric level, I'd say otherwise, but any cleric with two braincells to rub together is going to PrC out unless he really likes turn undead for some reason. The ability needs that at the very least to be brought up to par.
Three times per day brings it out of the realm of "too awesome to use". Two times per day would really just change it to "once per day and then too awesome to use".
Three times per day means the cleric will actually get to use the power. However, at this point you may want to bring it back to just cleric level instead of caster level.
Don't shake hands with the guy wearing a skull as a necklace.
obnoxious
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