Series 1 was great fun, exactly as it should have been - lots of monster hunting, adventures, magic, interesting characters and relationships, changing timelines, violence, sex, comedy, horror... Just pure fun etc. It wasn't GoT but every episode was enjoyable and you didn't know what to expect. It had an overarching destiny story but didn't take itself too seriously. 8/10.
Series 2 has been, for the most part, astoundingly dull. A couple of decent episodes, but 80% of the screen time is just people talking seriously and slowly in a dark room. They tell us about events rather than show them. The show is called The Witcher but he is no longer the main character. The second main character lost her magic so hardly featured either. The showrunners completely lost the main idea of the show. When I want to watch a drama I will watch Downton Abbey. 3/10.
I will not be bothering with series 3.