Too complicated? ... Well, you weren't kidding when you called them casual. Still, it's the easiest prestige class in the world. "You know what your cleric does? Well, he still does all of that, only better. No, he doesn't do anything new, but you get to apply these beneficial modifiers to his class abilities." How long has this player been playing? I'm not trying to be mean or seem down on them, I'm just curious. I just can't imagine anyone playing a cleric of Pelor that wants to be good at turning and healing turning down Radiant Servant when it costs them nothing, and they gain everything.