The problem is your translation. Or should I say, expectation?
Nothing in this universe is perfect. You consider 10/10 as perfect and top for eternity.
The truth is all masterpieces have a flaw, a flow that reminds us nothing can exist without one. A true artist knows a flaw is necessary and adds one deliberately if something feels too perfect.
10/10 does not mean flawless godlike. It just means a masterpiece. TW3 is a masterpiece.
By searching for only one 10/10 game that'll top everything else, you're still not worse than Escapist that set DA2 score to 100% or IGN who places 93% to utterly broken products.
Masterpieces should never be compared with each other. You can't say Bach's fugue in D-minor is not 10/10 because Vivaldi's Summer Presto is 10/10. One masterpiece does not exclude another.
btw my grandmother, both of them, wouldn't think TW3 is 10/10 game. They're both dead, but when were alive, they didn't believe something like TW3 can even exist. Hell when they were young, they thought TV is a fairy tale, an impossible thing. TW3 is 10/10 to all of us who wanted to see it realized - for decades.
One additional thing though.
A goddess who can do anything. Trapped just because. And can escape by a blink.
Waits for a penis to come and "save her"?
That's not a masterpiece. That's bullshit. Details are on cracked.com.
No, I don't think 10/10 is perfection. But, as I said, I think it means all "key" features are well done - or you should definitely not rate it 10/10.
10/10 should mean there's no reasonable way to significantly improve the important parts of the game.
Let's say you didn't care for combat, progression and loot. Those things combined, in my opinion, represent a very important part of any RPG in the style we're talking about.
So, I'm going to have to assume that if people rate it 10/10 - then they at least LIKE all those aspects to a reasonable degree.
If they don't, then they've failed as a competent critic.
Well, that's my opinion, nothing more
Also, I do NOT consider Witcher 3 a masterpiece - far from it. I think it presents itself as this huge open world game - and it fails utterly in many key areas when it comes to appealing open world gameplay and exploration.
No, it's a very good - even great game - and that's down to excellent writing, C&C and fantastic production values.
Personally, I'd rate it around 8.5/10 - with my objective glasses on.
With my subjective glasses on, it's more like a 7/10 game.
To me, a masterpiece is exceedingly rare. One example, in my opinion, would be Last of Us.
To me, the important parts of that game are all at least good - and most are great.
But it's not a 10/10 game. That would require these important parts to be as good as you could possibly expect them to be, given modern standards.
I can't think of a game I would rate 10/10. Not off-hand, at least.