I don't think first-person would necessarily make The Witcher 3 a better game, but damn this looks cool.
The mod, created by insane0hflex, adds two new horseback perspectives to The Witcher 3: over-the-shoulder and first-person. Both are neat, but I don't know; there's something about seeing The Witcher 3's war-torn world up-close-and-personal -- through Geralt's man-cat eyes -- that excites the hell out of me. There's already such a sense of place to The Witcher 3. Getting to properly inhabit it strikes me as a damn cool prospect.
Of course, the mod only works when you're on Roach, for now. No running around or fighting or lustily flirting on foot. I imagine creating a mod of that sort would take a hell of a lot more work, if it's even possible (given that complex custom animations would probably be necessary).
It would be a pretty amazing thing to have, though. I've always respected CD Projekt's decision to draw a line between Geralt's identity and the player's. He has distinct motives and his own personality; we never quite get to be him like we would our characters in, say, Skyrim or Fallout. So in that respect, a third-person viewpoint -- a slight disconnect -- compliments the series' gameplay and story. Still, The Witcher 3's world is so lived-in and detail-rich. I'd love to just soak it all in.
For the moment, though, horseback is much better than nothing. Have at it!