The people who think that move is OP are either (1) very bad at reacting to a move or (2) spend 95% of their Tekken play online and have never played a Leo offline. It doesn't matter if that move has crazy properties; the moment you realize just how reactable that move is, it's no longer the overpowered move you think it is Most of the time, the people who cannot react to i21 lows with obvious animations are those who are too focused on their own offense and neglect their reactions. The next time you play against a Leo, spend a few seconds Turtling and waiting for them to do df2+3. You'll find that you can duck in time if you're locked in. Want to practice this skill? Go into practice mode and have Leo randomly perform d2 (i21 mid) and df2+3 (i21 low). Eventually, you'll be able to discriminate between the two and build muscle memory. Yes, the move is not as reactable online, but the solution isn't to handicap a move for online play, thats just stupid.