I think it would have been a richer experience as a lot of the names/places still flew over my head, you don't really know the backstory with Dijkstra, Zoltan, Roche, Shani, Radovid and loads loads more. But none if it is essential, just "nice to know/remember" and tangential to the main plotlines - so I don't think it's worth playing the other two first just for backstory. I think Witcher 1 in particular, the combat is very dated.