Witcher 1 Geralt was certainly the most book accurate look from the games. That screen test also looks a fair bit like- and apologies for triggering any PTSD- The Hexer's Geralt minus comical painted on stubble. I'm not a big fan of the Fabio hair for practical reasons ("I swear I was winning vs that Striga until she tangled my hair in her talons and scalped me!") and because it makes it look like a Rhaegar Targaryen/ Lucius Malfoy screen test instead but I can live with it.
As for Triss... she doesn't look anything like Triss in either book or game and looks older than Yen rather than younger so there's not much right with the casting based on physical appearance. It's a slightly more significant change than going from chestnut hair to orange/ red as in the games. The casting overall is pretty trolltastic- apart from having all Geralt's love interests be coloured women they've also cast a Mikkelson, but not Mads and not as Bonhart.
On the more meta side of things, unless they tone down other aspects of the world, characters, and Geralt a lot the kind of people who would applaud things like Triss's casting still won't watch the show because the source material fundamentally won't be to their liking*. So all they're doing is annoying some people who would watch the show to appeal to people who won't. Frankly, that's been a major problem with a lot of Netflix programming overall recently and a contributor to their spate of poorly received individual programmes.
*Who am I kidding? Most of them are too busy looking for things to be offended by on twitter to bother actually watching stuff.