Curse picked not to lose instead of picking to win. They saw that Shyvanna was banned while Renekton and Mundo were still available and said, "We can get all the top OPs!" while completely forgetting that their star player plays "carry" top lane, not tank. It's the same problem Quas always seems to have: he gets to the big show and his team says, "Hey, we know you're famous for playing crazy top lane picks and carrying hard, but this is serious business now so play Renekton please."
I'd almost say they were baited at champion select. Like someone on COG said, "Hey, they'll always take Mundo/Shyv/Renekton if they're up, and Voy will always take Kassadin or Nidalee if they're available. Do you think they'd actually be dumb enough to try and build a team out of that pile of jank if we let them have all of them?"
Sometimes you've got to let the "OP" champion go and pick the one that actually makes your team composition work properly.