Worst in RPGs in general is pretty broad territory to cover. I will say that FFXII is notable in that the ostensible protagonist and the actual protagonist together cover both categories of bad protagonist you mentioned. I don't think I'd go so far as to say worst in all RPGs though.

I don't know if I can count the protagonist of Suikoden IV, because he's silent, but everyone else in the game, especially Snowe. Maybe Snowe counts. Probably closest to being the proxy protagonist.