Do you think The Witcher is better than Fallout 4?
I think yes.
I've been playing F4 at my friend's place (cause why buying it when I can go over there, right? LOL) for some time now, and TW3 is definitely the better RPG between the two.
I've been reading that F4 feels more like an FPS than an RPG, and I gotta say I agree. The RPG elements are luckluster (although not completely absent as some people make it out to be), the dialogue system is pretty janky, with very vague choices of lines, and are not nearly as well written and TW3's.
The quests I've been playing the vast majority of the times consist of a clearing mission, as in, killing stuff. Not very interesting in the slightest, while in TW3, they're so much better written and intriguing.
Skills and perks, in Fallout 4 they're mostly passive, percentage increases and stuff like that. Also Skills from F3 and NV are gone.
In TW3 there are passive ones, yeah but a considerable amount are active ones like alternative modes for Signs and melee attacks and defensive techniques.
Overall TW3'd char development system is a lot deeper.
I can't complain about their open world, Bethesda did a good job, they hardly fail at that, interesting places and exploration is rewarding. Same with The Witcher 3 though, with the difference that Novigrad stomps on Diamond City any day of the week.
Graphics, there's no contest. Witcher 3 wins.
Audio, both are really good.
Atmosphere, well, this is a subjective one, especially since the settings are different, I'd say both convey their respective atmosphere very well. Imo, the highlight in F4 is when you're exploring an area, on your toes, and a Deathclaw comes out of the underground and you gotta fight for your life. That's awesome.
As for TW3, there are some areas, like Fyke Isle, that are dripping with creepy atmosphere, ghosts and such. Always very atmospheric when you enter a forest and suddenly it becomes dark and cloudy, and you find out you just entered a Leshen's territory.
Story, I can't comment on that, I barely did the first quests in F4, but I hear the storyline ain't that great, and not terrible either. Kind of a meh.
TW3 though, was gripping and interesting to follow, always wanna know what happens next. Pacing was excellent too.
Combat is not really comparable, as you can imagine, they're completely different.
So my opinion is that yes, The Witcher 3 is the better game, and by far the better RPG.