I bought this game on the 7th, and I already have 35 hours in it.
Been enjoying myself so much that I immediately went and purchased The Witcher 1 and 2, excited to play those eventually.
In the first area of the game, White Orchard/No mans land, the scope of POI's/Sidequests felt about right, and I went to every POI in the area.
However upon getting to Velen I've chosen to stop doing everything and only do things that seem interesting. There's simply too much and I don't want to get burnout.
For example, I didn't help the pellar after I was done with him in Family Matters because I hated the character. I will say though, The Witcher 3 does a much better job of handling an "open world" than Bioware did with Dragon Age Inquisition. I hated that game, it was 99 percent garbage filler content. In TW3 at least, there are sidequests with actual effort put into them. Sidequests that many players may possibly miss because there's a good amount of them. One example is the quest in Velen where you have to clear monsters out of the ladies manor, but OH SHIT SURPRISE Letho is chilling there and we get to explore some content with him.
Anyway, I also wanted to say that I find the characterization incredibly well done. There are some characters I ran across, that I just fucking hated. I didn't want to help them, I felt legitimately frustrated playing a fictional fantasy game. That strikes me as an example of quality writing. Then there are others characters that I really vibe with and want to complete every quest associated with them. Like The Bloody Baron, that guy is awesome.
There's a lot of love put into this game, really can't say enough about it. Just got to Novigrad and I'm looking forward to more and also exploring the other two games.
Side note: Gwent is my favorite minigame since Triple Triad.