All good points but there's something more fundamental. You can't play Skyrim for 15 minutes and get the same out of it as you would of an hours gameplay yet here is this game with arguably more broad content and it's divided into chunk based gameplay. I don't even know what it is I'm describing but I know one thing, the TLC in all the points mentioned above is probably why it excels still. Anyone who has played it through knows how big it is but it never feels that daunting cause of this chunk based design where all goals are woven together from big quests to small and even the design of the world and placements of content seem to have some kinda of logic to their distance. It's perfectly packed as to not mis content but also feel like you're discovering it adventuring. No content feels repeated, even though there are a few monster repeats like early on with Wraith contracts but they feel very different.
Then there's the story, every little bit, tiny quest is interesting as the main story. It's also a rare sequel that fills you in on lore perfectly, I read two of the books later, watched a good chunk of the first game and played the second and I feel like I had learned the vast majority of the world and Geralts previous situations in the games after his amnesia and I never even noticed they dumped that on me. The vibe is only beaten by RDR2.
I struggle to get my thoughts on this game out or explain the feeling it gives me. It's pure perfection even with the slight annoyances like Gerald's movement indoors and igniting candles and what not. Even the villages look the same but this matters not, they still work perfectly despite being copies shuffled around. But then there is the little really witty bits you'll find every now and then, for example the quest with the priest who had taken a vow of silence, there's a lot of levity like that in the game and as with DOS 1&2 it creates a comfort even though Velen is a shit hole and that's another thing, the world never feels like a shit hole even though it is a terrible place. Also only game ever I wanted to read the side stuff, all books, descriptions glossery and most of all the beastiary.
Arghhhh. It's just too good. I feel bad for people who play this game on easy difficulties and never see how it comes together and why reading those passages on monsters is important or the systems for gathering and crafting. People with no need for oils, potions or master gear.