there's also the silver sword / steel sword thing which I thought was really poignant and interesting and said something quite thematically interesting about the Witcher's role in society, literally carrying a "but what if mankind is the real monsters" allegory around on his back at all times. and again, the show doesn't need to do this, they could just ignore that to make screen time for other stuff, but then they periodically drop in an out-of-place line about silver arrowheads or something!