See, I find that Prayer of Desperation to be much less useful than pretty much any other card in Fanatic's deck.
Fanatic is one of those characters that runs on dealing damage; eating her Play and Power phase without dealing any damage is anathama to me. If she's anywhere close to "default", Prayer of Desperation is only going to pull 2-3 cards. It's only in the rare occasion where multiple discards have been forced that Prayer of Desperation is worth playing. It's so situational as to become discard fodder for me 9 times out of 10.
Yes, it could combo well with Divine Focus, but...that's also at the expense of pretty much every other option. You'd have to either commit to using your hand to fuel Divine Focus or let DF drop in favor of other options.