I'd remove the requirement to learn forms. It's silly. The minimum bending skill requirement. You aren't going to take a seed if you can't reliably make the DC.
Overbending still irks me a bit. It needs to stay, but it needs to go. It's simultaneously too crippling to use, but without it this becomes overpowered easily. It still confuses me and makes me want to shoot it.
Agitate Dust still needs that method to overcome stronger winds I feel. Otherwise, it might get overwhelmed by other abilities. But you know what? I say leave it for now.
Change Flowing Air Strike to -5% concealment for every 4 you use.
Heavenly Stride seems a tad weak. Not sure though.
reduce Shockwave to +10 exceed to increase damage. That will yield at level 20 2d6/BL for a still potent ability, but not over the top on damage.
Soundbending (Windwhisper) needs an action to move the area. I say it is part of the maintain action.
Twister needs a direction and distance to throw targets. 60' and use a thrown weapon chart to determine direction (1d8 clockwise) seems reasonable.
What does Wind Barrier do again? It currently does...nothing of note. I allows people to make a reflex save to move 5'! And that one augment does something! But the base seed does nothing. Was it supposed to be a copy of Water Shield (or whatever it is)?
Earth:
Armor: You realize that this seed negates class features, right? The wis to AC one in particular? Have it count as medium armor for everything but class features (counts as no armor for that) and it will be fine.
Dust Cloud: see Agitate Dust. Also, Sandswallow seems to negate the need for the other base part of this.
Fire:
claw of the Phoenix is too much damage. That's 4d6/BL eventually. Granted it is a full-round action, but I fear it may be a tad too much.
Combustion and Explosion need work. Not sure what, but I do know that Combustion needs augments (and not a damage one), as does Explosion.
Heatwave needs a nauseating augment. +10 should do the trick. Possibly a DC increase augment as well, but I doubt it.
Pyrotechnics needs work as well, namely augments (everything should have an augment, to avoid making them increasingly useless at higher levels).
Sweeping Flames and company need discussion and work, we don't need three ways to attack an area with fire, awesome though it may be to attack things with fire.
Wall of Fire needs to do something other than catch people on fire. That's 1d6/round max, so it's not all that hot. It needs to either resist movement through it or deal damage or something.
Water:
Water Whip used to have +BL in damage. I miss that. That makes it actually deal something remotely viable.
Golems:
One thing I'm worried about: it can be hard to make this viable if you have to spend your actions making one other thing at a time and only being able to control one at a time. So it needs to be a lot better than you (i.e., contribute more readily), or you need to be able to control more. I vote for both: if you control one, it becomes a beast in melee, rivaling that of a totemist. If you weaken it, you can control more, or retain actions. So you can control one of moderate power (a little less than you) and still have a move action and swift to play with, or a really weak one (like 2/3 you) and still have a full round (use a swift to control it) or a strong one (125% of you) and spend a full round controlling it.
Feats:
Dextrous Combatant....I'm thinking that since it requires Weapon Finesse, we give it +dex to damage as well (not replace, but in addition to str)
The Combat Reflexes line.....is a little weak. It's too many feats to expect someone to spend on this (feat intensive) style. How about on the second one it's +wis to # of AoOs/round and +wis to damage, and the third one is infinite AoOs and +wis to attack and dex to damage. Does that seem too much?
Intuitive Attack is one of those feats I hate (justifying a fighting style with a feat, rather than making the fighting style better), so I'm thinking wis to attack and damage.
Channeling Gauntlets are off in both price and what they give. It should probably be a +1....+8 single steps rather than increments of 2. Also, I can't find a pattern in it. Finally, we need to talk about weapon special abilities and bending. I think we should just offer the opportunity to be as good as weapon abilities without using them. This means damage and enhancement bonus, basically, so a +8 eventual item will suffice (before epic, that is).