Can't blame them on that.
In every forms of entertainment nowaday, originality is pretty much dead, name it video game, anime or movie. Producers and Directors alike are even afraid of being "different" because they can't make much money with that, and plus the economic breakdown around them, they are all trying to make a living.
I personally prefer nice execution over originality though, an original show with bad execution is still bad, unlike a stereotypical show with outstanding execution.