Oh God...I can't even imagine playing something like The Witcher III. Persona 3 and 4 were timesinks, but not in the way that longer non-Japanese RPGs can be for someone like me. I recall putting 200+ hours into Morrowind and never touching the main storyline, so I think it might be more difficult to finish something even remotely similar (I'm still open world ignorant, so that's the closest and only example I can think of).