I personally don't like PC new game because you have to upgrade your computer (CPU,RAM,Video Card) for those game. I just think it is too much for me that on top of the game price I still have to pay for those hardware upgrade. What's worse is almost each new game require more and more, it's a never ending story. That's why I prefer buying new console game not PC game, and why I like this site for offering old game. Well, I think GOG doesn't need to offer *very old* game, games that are two or even one year old is fair to me. But to tell the truth, I don't like the idea of *new* game offering here. It looks like to me that GOG is distracting their philosophy. However, if it is business terms and deal with the game company for those company to offer games to GOG then I will feel more comfortable.
Don't worry, it's just for this game, and maybe other titles by CD Projekt, the company behind GOG.com.
As for new games, well, it's generally best to leave them for a few years, since you generally need to upgrade every few years anyway. You just pick up the titles as they become playable to you, and by that time you have the patches and the hindsight on whether or not a game is good.
From the minimum requirements I've seen for The Witcher 2, though, it doesn't require too much, but I've yet to see the recommended stats.