Wouldn't Eva Green (Casino Royale and The Golden Compass) make an outstanding Morgana? Definitely a better and so more interesting Morgana...or is it just me? :)
She was Morgana in another tv show (Camelot) anyway. She did an amazing job there but unfortunately the show has been canceled recently and that really makes me sad. Eva was an amazing fit as Morgana but I think Katie does an magnificent job too. They both are great actresses and they both act soooo good as Morgana. :)