There's no such thing as "objectively bad," IMO.
Subjectivity often doesn't play a role in ranking, which is one reason why I brought it up. Ranked maps aren't supposed to be "good" in a subjective sense (because that is, well, subjective).
Things like Lemon Tree are objectively bad and that can be looked at by a computer as "shit." A computer is only as good as its programmer, though (no offense to the dev's of course), so objectivity can't be completely encapsulated in a program.
Remember, ranking isn't about like/dislike; it's about sticking to the criteria. BAT's filter maps; they don't move them into ranking.