The whole Vain Sorceress thing makes no sense. Almost all girls with Gift that are sent away by their parents are either disfigured or from extremely poor families. Or both. This is explained that no-one wants to sent away their daughters, because that means no heritage. But in given settings women don't inherit anything, are a trading good in marriage and are expected to do nothing more exept being good wives and mothers, no matter what is their social status. And marriage means dowry. It's also common knowledge that people with Gift are in almost all cases sterile, so there is no real chance that your daughter will give birth to bunch of kids. On the other hand, magic users have access to trendemous power, both literally and by means of diplomacy and wealth. So if everyone is so pragmatic with family management, the best way to use your Gifted offspring is actually sending it away for magical training (which goes for free and you are paid for it) and then raking actuall profits from having a sorceress in your family.
None of this happens, because author needed a steady pool of Broken Bird characters.
The issue of infertility is described in unclear terms. On one hand, many characters react as if it was magic itself that was the cause of infertility. On the other, it was stated outright that — at least — one very influential magician called for forced sterilisation of magic adepts, specifically to prevent uncontrolled proliferation of magical talent. Regardless of any other conclusions (or cans of worms to open), it implies that magic doesn't cause infertility in every case.
Population. It's stated numerous times that humans came to this land at some point in the past, sailing from somewhere. Word of God says that humans landed less than five centuries in past, in group of less than ten thousands. That means Writers Cannot Do Math combined with Artistic License - Biology - human population in short stories (which take place a generation before saga) is counted in millions. To actually reach so high numbers humans would have to literally mate like rabbits with zero fatality before reaching maturity. To made this worse, there were two huge wars during that period - Last Stand of elves and war known as Falka's Rebellion, the second one being a rather recent blood-bath spanned across nations. Not to mention smaller wars, diseases, famine, monsters...
We know that the elves somehow opened a cross-world portal and evacuated from the dying world. But how exactly did they manage that? The elves from another world can only manage short jumps, and probably couldn't help with such a big project.
In The Blood of Elves, Geralt takes an elixir in preparation for a fight that increases his combat prowess but has the detrimental side effect of lowering his rationality and reducing his control over his emotions. When he sees a group of assassins approaching, he notes to himself that he doesn't want to kill them but that if a fight starts he will have no choice, due to the elixir's effect on his mind. And indeed, he is so overcome with anger during the fight that he butchers all of them in gruesome ways. However, before his fight with the striga in The Last Wish, he took several elixirs that had a similar effect on his combat prowess but obviously without the drawback, as he maintained strict control over himself during the course of the fight. He was very careful to hurt the striga without causing any lasting injuries. So if Geralt has elixirs that can enhance his abilities without robbing him of some of his mental faculties, why didn't he take one of those instead of the one he used in The Blood of Elves?
As I recall, the elixir he took in The Last Wish only enhanced his senses to a supernatural degree, allowing him to sense the Striga's position perfectly at all times. He did the fighting itself with his own skill.
Why, in Lady of the Lake, do Geralt and Yennefer decide to commit suicide? I mean, I get that they think it's Better to Die Than Be Killed (and given Nilfgaard's methods of execution they're probably right), but Yennefer is no longer wearing her Anti-Magic shackles, so she could just teleport them to Kaer Morhen the instant the guards looked away. Is it just a case of Honor Before Reason, since they promised to follow through with it?
And what would they do next? Because for sure not living happy ever after. Ciri stays with the emperor, no matter what they do. And the emperor wants them dead, but in his courtesy he's leaving behind a dagger. So no, they have no reasons or purpose to escape, since there is nothing left for them to live for.