I totally know what you mean. The beginnings of both games are really tough to get used to, especially if you're coming off W3.
After trying many times over the years, I eventually found easier W1 to get into, once I got used to the fact the combat is essentially a rhythm-clicking game.
Also the beginning area isn't very compelling but once you start helping people on quests the story really opens up and pulls you in, especially after you beat the first big boss -- which unfortunately is one of the tougher boss fights you'll encounter because you're so weak in terms of weapons and skills. Once I managed to kill it, I felt a real high, and I started to really enjoy the game.
Like you, I also read the books, so that also helped to keep my attention in the game.
I don't know why, but while W2 is a way less janky game than W1, I just found the interface and combat really awkward on the PC, even if using a controller. You can tell it was really designed for consoles. You can't remap some of the commands (maybe with the mod you can), and it took a long time for me to get comfortable with how the game works. I actually started to miss the rhythm combat of W1.
Both games are definitely worth playing if you big Witcher fan, but for some reason I think I may slightly prefer W1 over W2. It has a certain charm that I liked and I liked the more compact size of the game.
Yakuza series -- I own almost every game now because of sales and Humble Bundle monthly/choice. I feel overwhelmed by the huge time commitment to play all the games, so maybe that's why I usually stop playing after an hour or two of Yakuza 0.
Skyrim -- I still haven't finished Oblivion with all the expansions, so I keep putting Skyrim off. I also need to finish Fallout 4 too.
Shogun Total War II -- I loved the first Shogun but I don't know why I haven't played the sequel even though I've owned it for years.
GTA5 -- loved every GTA before it, but for some reason whenever I start the game up, I just turn it off after driving for a little while. Maybe I'm burnt out on the game's formula now?
Nier: Automata -- I keep hearing how awesome this game is, but maybe the hype is making me delay playing the game as I fear that it won't live up to the hype.
Master of Orion 1 /2 and Master of Magic -- I loved Civilization 1 to 3, but I grew up reading sci-fi and fantasy so I really want to like MOO and MOM but maybe it's time to accept the fact I'll never really play them. These games are really old now. I still own the original boxes and floppies for these games (although I have digital versions now).