I only bought 3 games in the last Steam sale...please don't tempt me! I want to actually shrink my Steam list of not-played games. *sigh* The zombification!

While TW 2 was a very solid game (certainly better than 1 in terms of pacing at least). It did make a few mistakes IMO.
1) For some reason, CDPR decided to add quicktime events to boss battles. They were not needed at all, and the new battle system was just fine without adding them in.
2) There is a lot of high-level political stuff going on that may pass over your head if you're not familiar with the history of the world and some of the events from TW1. It all comes together in the final act, but if you're not paying attention to the game's dialogue and lore, you'll likely miss vital points.
3) There is a major choice to be made in the first act of the game which will lead to the second act being one of two completely different experiences. This will necessitate that you replay the game at least once or miss out on an entire chapter's worth of content which is blocked by your having gone the other route. While this is isn't necessarily a bad thing, you should probably be prepared for your two playthroughs of the game if you want to see all the content.