After playing both BloodBorne and Witcher 3 (didn't finish yet), I would say that first-of-all the two games are not comparable. You don't play Withcer 3 for combat, or even RPG progression, you play it for story full of great characters and interesting developments. You can roleplay the Witcher on highest difficulty or you can drop it down to Easy and still enjoy the heck of the story, sidequests, lore, exploration etc. BloodBorne is about execution and even if you don't get what the story is about the challenge and overcoming overwhleming odds is all the game is about. There's no difficulty seting or a story that 90% of people playing will understand.
Second of all, if I had to choose the GOTY, I had much more fun with Bloodborne so far this year. This game just gives and gives and executes what it aspires to flawlessly. I was enthralled until I finished. Witcher 3 is so big it becomes overwhelming and it's not what I like to feel in a game. The game also has a bunch of minor annoyances, like easily outleveling content, movement (Roach!!), cluttered menus. It would be definitely the best game last year when the best game was the very mediocre DA:Inquisition, but this year we are blessed by a cornucopia or great games which is fantastic but also daunting at the same time.
Nevertheless, it's easily the best WRPG of the year, and I will certainly finish it. To the OP, you won't get any better WRPG game, but maybe you stumbled into the wrong genre.