I played the Witcher games...all 3 of them. And in the right succession of numbers, as well.
I got bored out of the Witcher games...all 3 of them. And in no particular order of numbers, too.
The Witcher games are not for me...but whenever I put my reasoning upfront and explain why I don't like the Witcher franchise as a whole I do get quite a bit of hate in the face. Furthermore, I actually advise people to not pay the full price of a game for any of the Witcher games, as I find the 'gameplay' component of those to be limited...but that's me.
Purely from a gameplay perspective, I think, the Original Sin franchise comes on top of the Witcher games. There is way more freedom for the player and innovative thinking to be had in OS. Just reading how people have overcome stuff in completely different ways than what I did is surprisingly entertaining, but also shows a level of freedom that is increasingly and worryingly becoming absent from today's...well, 'games.'
My gameplay experience of OS on Tactician, right from the bat, is that if the game does not present new challenges I stomp through the combat. Original Sin has things that can one shot your entire party in a turn, tough environmental hazards, ridiculous traps, true dungeon crawling puzzles, opponents possessing aoe op skills that can charm 3 out of 4 of your party and many other things...But the solutions to those are left to the individual player and how they choose to act. That's the good news.
But obviously gamers such as myself are perhaps the smaller part of the whole demographic.
