How do you evaluate the defense? I'm not throwing shade - I'm honestly trying to learn the game better. I'm an analyst so going by the numbers I would look at Total Goals given up, average goals against, and then probably % of games where they give up a lot of goals (win or lose). I'll choose 10 since it gives us a nice data distribution.
So even if you throw out the teams who haven't played 91 Madlax is only 4th of 7 - again based on the data.
How are you ranking them first? Is it based on how they play together? I know it's hard to quantify team work. Or how they "ride" or "body" or "hands" (things I hear people scream at the defense). I know there are other things at play - for instance the 91 offense makes the 91 defense look good statistically. I'm guessing a weak goalie could make a strong D look worse or vice versa.
Teams haven't played the same number of games (e.g., 91 => 6, NL => 5, True => 4) so data is skewed even without considering who has played who. You would need a lot more statistics to be able to quantitatively evaluate each teams defense, which I doubt even each team is doing. So either way there is going to be some inherent bias in any ranking because you either are using a limited data set on teams with uneven schedules or its based on "look and feel" or "gut feeling". If you had enough data you could consider Attacking Possessions, Goals Scored per Attacking Possession, Man Down Defense Opportunities vs Man Down Goals Against.