Indeed, and those are games I usually pass on. There are exceptions but it's usually a friend pestering me to play it (like TW2 which I ended up really enjoying after all but would rather have had all the branching plot and political intrigue but with a customized character)
Geralt is not so interesting he couldn't be replaced with a player created avatar imo. The only reason he isn't, I think, is probably because they feel he works as a proxy stand in for the majority of their straight/male audience.
I know the witcher series is based on books, but so is their next one, Cyberpunk 2077, but the rumor is that WILL feature character creation (and hopefully gender selection, but news on that game is understandably sparse so far).
I loved my time with the Witcher game, and I know I will play the third when it comes out for all 100 hours worth of content it says it offers, however, I know I'm going to go right back to Dragon Age: Inquisition after beating the Witcher, because the value of the character creator is so enormous. I mean, to see every race, class, and voice alone requires at least 3-4 playthroughs-and those are huge differences right out front. That seems like each run through is an almost entirely different game from the very first moment. Certainly not trying to start a flame war here, I'm just so SO excited by the unprecedented level of customization Bioware seems to be giving us for this game. The four voice actors thing still floors me.