While today FFXIII-2 is not the worst in the series (unfortunately FFII has to retain that dishonor to me), I simply can't bring myself to like anything this game has to offer: I dislike the storyline, the characters, the simplified combat system, and overall the raw attempt to a continuation of my least favorite mainline FF game.
However controversial it may be, I think XIII-2 is worst than its predecessor, and that the sub-series should have just died with the first one.