I must preamble the main premise, with my own terse opinion of TW3 and the semantics of the question.
The Witcher 3 isn't my favorite RPG, which I feel qualifies me to posit this question; is the Witcher 3 the BEST RPG ever?
Not your favorite, but as ultimately a product of entertainment, is their an RPG that is not only as kaleidoscopic, but so accomplished across its many facets as to challenge or supersede the witcher 3 as the best RPG ever?
There's a paucity of RPGs, if any that can offer excellence (or at least purported excellence according to the larger gaming industry) in: Storytelling, theme, narrative, aesthetics (the Witcher 3 is possibly the most beautiful rpg ever), characters, accessible yet pensive combat and RPG mechanics, choices & consequences, lore, characters, enemy types and variety, variegation of environments, and a PC that isn't entirely stolid without being invasive.
Without belaboring the point TW3 isn't my favorite RPG (that would be New Vegas), but I'm struggling to think of an RPG that offers as much as the Witcher 3 across a greater number conventional RPG facets, is there one?
I'm very tired, so please excuse the grammar