We reported on a previous mod that added a first-person camera to The Witcher 3 back in 2016, but the download page and video demo for that project seems to have been removed.
Luckily, crthdr at NexusMods has released his own first-person mod, and it goes even further than that original 2016 project. Gervant in first person makes the whole game playable in first person, even combat.
Now, I’m not entirely comfortable with tackling The Witcher 3’s most difficult fights in first person, but it provides a useful transition to one of my favorite features of the mod: an assignable switch to switch on the fly between first person and third person, similar to how The Elder Scrolls or Grand Theft Auto 5 games officially implement this feature. Crthdr is even working on first-person versions of The Witcher 3 cutscenes. I don’t think I’ll use this feature, but I respect the ambition and technical know-how required to implement it.
A change of perspective can sometimes be just the thing to freshen up a well-worn experience. I played the first Witcher with a shoulder-mounted camera in the Enhanced Edition many times, but I was really overwhelmed and looked at things with fresh eyes when I tried the isometric camera mode from the game’s original release. I think I’ll use the crthdr mod the next time I replay The Witcher 3 (after I’ve beaten The Witchers one and two again, of course).