Personally I prefer 1 to 2 - Plenty of Witchering to do, not too political plot, more in tune with the books ~ Although Geralt's sudden urge to sleep with the whole female cast lost me a little.
I think the Witcher 3 brought back that feeling from the first game, Geralt - As with all Witchers - are politically neutral and while Geralt clearly only stayed by Foltest's side because he wanted to remain with Triss, the rest of he Witcher 2 he is getting very deep into politics, and in the case of a certain country makes a very important impact, which while a very good game is a bit odd - Geralt is held to the games plot by force, if he doesn't meddle with all these conflicts he cannot clear his, and Triss' name - He is a prisoner to the plot essentially.
However I can see where you are coming from a sense, the loss of this heavily political plot for a destiny one is a very big jump, the Witcher 1 & 2 were a little more grounded, but as this is an event that was a long, long time coming its not really a surprise.
I still think that 3 takes the best of both games - Pretty good combat, Nice world and worldbuilding, believably crafted story and characters (some inconsistencies but its still waaay above the standard) and a lovely amount of polish.
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As for further expansions I would love to see more, plenty of world left to explore, I want to see some of the other countries and some end-game expansions set in the world that you crafted during your playthrough with all the results of your choices to see.