After playing a lot of Witcher 3 lately, I've got to say that the claims that it is bigger than Skyrim really..... aren't true at all. In terms of amount of content, they're actually about the same. And Skyrim actually has a lot more to explore. And significantly more ruins, caves, and dungeons to explore than Witcher 3. While Witcher 3 has far more settlements than Skyrim, only about 75% of them are actually inhabited. And of those, maybe one in four will not even have any sidequests at all, and then the rest will all have just one. With only major centers of the main story having more than one.
And even though it technically represents a larger area, and the in-game world is much, much larger than Skyrim's, there's way less in it. And most of the area is actually empty space between locations. And most of the locations on the map that you can "explore" are just a treasure chest, or a map to a nearby treasure chest, protected by one or more enemies and that's it. Not the intricate and complicated optional locations that Skyrim had. The only really complicated locations in the game are in main quests, or sidequests that are "spun off" of main quests. Typically with a character in a main quest asking for your help with something else after you get their help in that main quest. Technically there are more "quests" in Witcher 3, but most of them are extremely short and simple and just can't compare to Skyrim's much longer sidequests that have more steps to them. The only Witcher 3 sidequests that compare to Skyrim's sidequests are the ones I just mentioned, the ones spun off the main quest.
Don't get me wrong, I'm really loving Witcher 3, and I'm going to finish it in one go, which I've never done with Skyrim. But the whole idea that it blows away Skyrim is very incorrect. What it really does better is story and dialogue. It does a way better job at that than Skyrim. And the combat is obviously a bit more fun. But Skyrim still destroys it on number of sidequests to do and their depth and intricacy, and on exploration and amount of stuff to explore. And I actually liked Skyrim's smithing system more than Witcher 3's.