There are SPOILERS.
I was so worried about reading "Blood of Elves" and spoiling myself season 2 of "The Witcher", it turns out it didn't spoil anything. Mostly because the book has little plot and while it was enjoyable on its own (I might like the book Ciri slightly more than the show Ciri), it looks like the writers just wanted more action and more characters. To be honest, I'd like it more if the story was focused on Geralt, Ciri and Yennefer and not the entire world, like in the book (I suppose the balance changes in following books). I knew some characters would come back, but did we really need every single character from season 1 to appear again? I'd like to see more of Jaskier and Nenneke, Vesemir was also an interesting character, I don't mind seeing Calanthe again, but why introduce so many witchers (and why almost none had white hair?), bring back Dara, follow so many mages (am I the only one who got lost with names of mages, kings, kingdoms, spies and plots? Starts to feel like "The Lord of the Rings" before I read the books) and mention every single event we already know? It looked like instead of developing the main characters, the show was more interested in building the world, for potential spinoffs, prequels or sequels. I like some parts of it, like explaining the Conjuction of the Spheres, but I feel like there was too many arcs and scenes and it lacked a proper structure. So many things happened in season 1, we saw how Geralt and Yennefer became who they were, Ciri got a lot of screen time for her walking and running. In season 2, it feels like Ciri was well developed, but I'd like to see more Geralt doing something else than fighting. I'd like to see Yennefer who doesn't have to fight for her life in every single moment. Those scenes when we see her and Geralt talking, when we see Ciri and Geralt forming a bond, when Jaskier finally appears and talks to Yen and Geralt - they were the best. I hope for more such moments in season 3.
My favourite is probably the arc in Kaer Morhen. For a moment, I really thought Vesemir would give Ciri the blood and start the mutation. I thought perhaps it happens in later books. It totally fits Ciri's character (and age) to want it, and I'm surprised Geralt wasn't more furious when he came back just in time. Her not being safe even in that secret place and not because of monsters, but because of people with their own agenda towards her was a great move and it gave Geralt a good reason to leave the place, like they did in the books. I like how book Ciri was childish and pure and show Ciri is driven by guilt and darker. And fortunately there was no time for her to talk with Yen about sex - I knew when I was reading it that it's not going to happen in the show, but I expected some awkward scenes with Jarrafrom the library and burst with laugher when he was killed in the same or next episode.
Jaskier got his hat and Yennefer only wore black dresses - someone listened to fans' complains. But I liked how they joked about the first season being too complicated. I knew nothing about "The Witcher" and loved different timelines. I just don't understand, if they did fanservice, where are some shirtless scenes with Geralt? Or anyone, I don't know, Lambert? Jaskier is certainly not what I would like. Okay, I know, last time they made Henry Cavill dehydrated for those scenes in the bath and that is absolutely not fine. And Yennefer stayed clothed this season, too. But there were women's breasts, I'm just talking about balance.
Now I know I can read next books and don't have to worry about spoilers - the show is going to change most of the details anyway. The only thing that surpsised me was the final reveal. I noticed that Ciri's father didn't turn to dust like her mother in Ciri's vision, but I thought perhaps the deadlines werer tough and the special effects crew didn't want to spend time on it so they cut early :D It was a good feeling, though, being surprised. I'm assuming the reveal was from the books. Maybe I won't read the rest of them after all?