primeval and doctor who were awful imo.
The appeal of robin hood is just how tacky it is - we've had a million gritty/dark adaptations of robin hood; a new take on it was sorely needed. The second series was a little poor I thought, but I'll still watch the third series when it airs.
I'll start to watch merlin when all episodes have shown (I don't watch TV, and I can't be doing with watching episodes a week apart).