The old Air Stance gave +1 to TN.
The new Air Stance gives +1-3 to TN based on School Rank.
While at low levels, where most people might playtest the Beta, this might not seem like a problem, at high levels Air Stance combined with Striking as Air isn't just optimal, it's a One True Path. Air Stance becomes better at avoiding Earth Stance at avoiding crits. While Earth Stance prevents Opportunities from being spent on crits, Air Stance does essentially the same thing by making your opponent keep all their successes to even land a hit, thus usually lacking the necessary Opportunities, if they even hit at all. Further, Air Stance stops crits from Heartpiercing Strike or Iaijutsu: Rising Slash, which Earth Stance does nothing to avoid.
At high school ranks, Air Stance and Striking as Air allow someone to average a TN of 8-9 while still maintaining offense. This high of a TN often leaves someone untouchable.
Worse, Air Stance makes combat BORING. Imagine two people who use it fighting each other. It creates a boring D&D-esque scenario of two high Armor Class characters swinging at each other uselessly forever. You can't even disable someone using Air Stance with crits that inflict a status because Air Stance usually disables getting hit.
The counter argument I saw was that at high school ranks, Air Stance was bad because it was only a +1 and this didn't matter. That is mathematically not true. While explosions and Void Points can raise kept dice, even at the highest ranks characters generally keep only around 5 dice. Air Stance at high ranks reduced damage suffered by lowering average successes, and made it harder to be crit by making opponents have to keep more successes as opposed to Opportunities. Combined with Striking as Air, the old Air Stance was effective at all ranks.
The change of wounds to fatigue helps answer complaints of the Fantasy that "I don't want to get hit in a fight" by stopping damage from meaning your character is sliced open. However, the new Air Stance goes too far and is 1) a One True Path and 2) makes combat boring and uneventful.
I have seen complaints about Earth Stance being too strong, but while that could be true as well, the new Air Stance is a huge balance problem at higher ranks.
Is this game only intended to be balanced at low school ranks?