idk, I thought HoS was great when I played it. Had lots of humor, good villain, good story.
I've always said that if anything is poorly executed in TW3, it's the main story. Too much of a break from TW1 & TW2 where it tried too hard to tie back to the books and left out too many of the themes explored in the prior games (especially TW2). It expected players, regardless of if they read the books, to have an immediate connection to Siri and Yennefer, who they've only heard of a bit in the second game, while kind of putting the more established characters into the background. Additionally, the wild hunt really wasn't as menacing as they seemed, had no personality really, and the final boss was kind of lame. Gaunter O'Dimm was a better villain than Eredin.
Coupled with the fact that the entire political side was just a joke, especially how they turned Radovid from an intelligent, but ruthless ruler into a complete nut job not worth siding with.
I still loved the game and think it's one of the best single player games I've played, but personally I still prefer the stories of the first two games. Honestly, I think if they redid TW1 in the new REDengine and brushed up the dialog a bit, it could probably be the best of the trilogy.