CDPR took Todd Howard's boast, "see that mountain, you can climb it," and added a tantalizing possibility that there might actually be something interesting on the mountain.
Dude, no. On the contrary, W3's world was utterly EMPTY and you could be sure that there would be fuck all on said mountain unless there was a map marker on it. Said map marker would mean that you will see some trashmobs there along with some generic loot, that's it. Open world was easily one of the weakest aspects of Witcher 3. Only in the DLCs did they put some effort into it so that the locations had some narrative behind them and usually had the world react to them getting cleared or made them part of some larger goal (such as rebuilding the statue). But main game? Engaging with the open world was an utter waste of the player's time.
I think it's a matter of perspective. Witcher 3's map certainly features generic filler encounters. It's also true that Witcher 3's absolutely garbage-tier itemization hurt exploration. But the game also has just enough highly polished side quests lurking around to give the player a sense of what-will-happen-around-this-bend that simply doesn't exist in e.g. Skyrim. The monster quests alone shit all over most things you can find in Todd Howard's Viking-themed playground.
You're absolutely right that POI chasing in Witcher 3 isn't rewarding. And I'm on record saying that Witcher 3 is overrated generally--cursed with bad gameplay, boring RPG progression mechanics, poor character-build variety, and an extremely over-padded main storyline, the length of which compounds all of the aforementioned problems. Overall, I'm not even convinced that W3 is a better game than Skyrim. But if your argument is that Skyrim had more or better polished side content, then I just can't agree. Side content is W3's overwhelming strength. The game's problem is that it doesn't have much else going for it.
And yeah, the DLC were a big incline too, but again, they were just an improvement on the same formula--narrative heavy, highly polished, "cinematic" presentation interspersed with braindead Witcher-vision puzzles and dodge-roll-spam combat--but more focused (and with less Ciri, lol).