That's a thing I find terribly sad. It is *very* easy nowadays to call an author "to be unoriginal", and that's like a whip in the face to me.
I'm since last year developing my own fantasy universe (from which some friuts you can see in the story "The Adorant" in this board), and I try to keep away from any clichés. That is, however, extremely difficult, nowadays.
Oh dear, I didn't mean to step on toes. I'm terribly sorry. And I don't even know if the that saying about 21 plots is actually correct. But as a writer, you know how hard it is to develop your own voice and avoid those cliches. It's very difficult but for me, that's the 'fun' and challenge of writing.
I'm creating my own world too. I've been working on it for almost a year and trying to be 'original' is the most difficult challenge of all. Just when I think I've found a new angle, I pick up an author I haven't read before and find something similar to my idea. LOL It's rather frustrating at times. But always remember, no one can tell a story in your own voice - from your own point of view because it is unique. And that's what keeps me going.
Good luck and I'll take a look at "The Adorant". Thanks!