Overall a great new discipline with good flavor. Here's some comments/suggestions/what-you-call-hem.
As to reviewing the power by level of everything, I'll see if its somewhere between the power of a typical spell or maneuver of maneuver of its level, doing relatively the same thing, if I find one.
Discipline Weapons: When I think of weapons associated with cold/winter, I think of a scythe (though Autumn fits better), a flail, and weapons used by the inuits (dagger, bolas, bow, spear/harpoon). Perhaps a bow would be in order considering it is one of the few disciplines focused on ranged combat.
Feat: Cold SeriounessSeems like three feats for the price of one more than a tactical feat, to be honest.
Almost all Tactical feat follow a similar set of benefits in that they offer three situational options the player may use. More or less as follow, in any order.
1st kind of tactic: Do this things, maybe only if you also do that thing and you get a bonus effect.
2nd kind of tactic: Do that one specific pattern, get a bonus next round, perhaps only if you do it again.
3rd kind of tactic: If that one easy to accomplish thing happens, you can do that one specific thing next round.
The tactical feats of a Discipline in ToB are special in that they all have a Discipline-specific feat as a requirement.
The ground freezing effect of this one is a bit problematic. Does it affect every square the character moves on? Does it last until it melts?
There is also already rules for walking on ice; they cost two squares of movement to move through and increase all tumble and balance checks by 5.
Allowing the feat the make "super ice" that is very hard to balance on should no be necessary considering nobody really puts ranks in balance anyways and that the double move costs should be more than enough.
Lingering ColdQuite a dangerous 1st level maneuver in that it is perhaps the only one dealing near-guaranteed damage (possible cold resistance, though low odds of them at that level) without odds of failure. One of the only level 1 spells offering that is magic missile but it is quite possibly out-damaged even on a fort save because the effect repeats next round. Perhaps it would scale better if the effect only begins repeating on following rounds at Intimidate rank 6.
Freeze TouchIt is like Desert Wind's Holocaust Cloak at level 1, but works once and improves. It doesn't have a clause concerning reach weapons though. Should it?
Flower Wither AwayProbably way too powerful considering it offers AoE damage so early on top of a movement debuff that could have been the whole maneuver on its own.
Damage on a failed save will likely be between 6 (roll of 1) and 16 (roll of 20). 1d11+5 on a failed save is a lot of damage dealt to more than one target at level 1. Mostly compared to other level 1 spells.
Cold SignIt is like Desert Wind's Burning Blade (a very good maneuver) but deals more damage and can be applied to any kind of attack, for every source of damage done in one round. The biggest danger with this one is that since its a level 1 maneuver a spellcaster can easily grab it with an item to boost spellcasting and wand spell damage to very high amounts if they have Intimidate as a class skill. I'd advise having it scale with initiator levels like burning blade instead and with the same range of damage.
Undulation RayFeels like a stronger version of Ray of Enfeeblement against dexterity that deals decent damage on top. Since it doesn't specify that the penalty can stack with itself I'll assume it doesn't. The real concern is that it has a strong potential to reduce a target's dex to zero with one application. Can it go below 1 and paralyze people?
Icicle ShotJust to wondering if standard D&D multiplying rules apply here. Double of a double is a triple, double of a triple is a quadruple...
Is the half of a half a third?
Icicle WeaponA very minor worry but it might be better to state that the weapon fades away or otherwise ends up leaving nothing behind. There are some artificer tricks among other things that make it possible to restore broken magical items and leaving pieces behind could be retardedly interpreted as giving something that can be repaired and so giving ground to magic sword multiplication.
Mystic Cold WindDiamond Mind's Insightful Strike as an AoE doing guaranteed damage with a status debuff on top. Very strong even for a fullround action considering maneuvers like Insightful Strike only really gives a move action for the rest of the turn (which isn't helping much in damage dealing and is mostly used to position for the single attack). I'm not sure how to work around that issue but as to every other maneuvers dealing Intimidate check damage I must say: Diamond Mind stopped at double the check result, and not for nothing. Increasing a skill check is incredibly easy - not to say absurdly so. Skill check to damage is dangerous territory especially when damage is dealt even on a failed roll. Multiplying that damage has a strong potential to bring one-hit kills against a CR of equal+ level. Or a few since its an AoE. Most of these maneuvers would be powerful enough if the debuff/status effect was all they did.
Frozen TechniqueOne of (if not the) best stance of every disciplines at that level. I do not say that it is overpowered though. I do find it funny that being slowed leads to 'speaking' becoming a move action. Entangle becomes a bane of Weapon Finessers everywhere.
Frost PillarsThis maneuver
rises so many questions but I'll go with two.
Is the definition of 'upward' relative to the user's position? (if he is spiderclimbing on the ceiling, can he rise pillars from the ceiling?)
What happens if the pillar flings a character against the ceiling or some other hard surface... or if the pillar rises so high that it crushes the target against the ceiling or some other hard surface.
Normally I wouldn't think it wise to give maneuver users the ability to create permanent structures. That's crossing the line between combat techniques and a spell, giving Utility potential normally given to spellcasters. They also have no limits on the number of use of their abilities and could produce obscene amounts of it. At least it melts anywhere but cold climates (though quite slowly). Unlike Cold Divinity there is no clause that limits the user to one set of pillars at a time.
Little IcebergVery neat.
When you initiate this boost you create a structure of ice around you that grants you total cover and concealment in both directions inside-out.
To avoid people somehow thinking it grants total cover and total concealment, you might want to rephrase it as:
When you initiate this boost, you create a structure of ice around yourself that grants concealment and total cover in both directions inside-out.
Ice BarrierBlocking almost anything as an immediate action is kind of unfair. It is quite like the spell Wings of Cover but arguably better and without that clause that states that a blocked enemy can opt to spend his action differently in response. Having that clause would make the maneuver less cheesy.
Otherwise it might be a good idea to switch the casting time with Snow Sign. Snow Sign wouldn't be too strong if allowed to be cast as an immediate action and making Ice Barrier a swift action would let your opponents the ability to contemplate other ways to use their actions (if they actually know how the Ice Barrier works), while still limiting them for one round in exactly how they can attack you.
Icicle RiseI'd suggest to actually rewrite the relevant information of Icicle Shot instead of referring to it. It will take about as much space and save readers the trouble of scrolling up and down to keep track of everything.
The text is slightly confusing though. The range is 25 feet per IL but the effect has no range on how far up it can make the ranged attack rolls.
The range being 25 feet per IL indicates that the effect must begin at a point within this range, and the text states that it comes from a surface (A bit vague).
Perhaps for clarity it would be good to mention that you fire icicles from a flat 5 ft. square horizontal surface within range. that makes ranged attack against target directly above them up to any distance.
they must come from a surface below you, and they can only travel directly upwards
Specifically stating that it must be below you seems like a bad idea.
Icicle BombThis is Greater Insightful Strike with a possible infinite range as an immediate action that doesn't rely on a successful attack roll to deal any damage. Nuff said.
Weapon FreezerIncreasing the cold damage inflicted by Icy Burst on a hit and a crit to the next die size would be more appropriate. Multiplying it is too big of a power boost.
The possible increase to the weapon's threat range should be static, for balance it should simply double its current threat range, stacking only with the Improved Critical feat. Basing it on an ability modifier gives too big of a chance for a crit threat each attack at minimal investment.
Blowing Wind-Ice TornadoSomething that strikes me about this discipline is that it offers many AoE abilities that have no risks of voluntarily causing friendly fire.
Tactically I believe its too good without some feat to somehow shape the effects favorably. As far as flavor goes, I think it doesn't fit. Winter and cold are merciless and shouldn't care who or what they harm, be them friends or foes.
This particular maneuver offers the ultimate battlefield control effect; wind, no vision, no hearing, ongoing damage, no ranged attacks against you, very limit movement, and your whole party can waltz through it.
To boot it allows you to stop that very same effect from being against you.
Perhaps it would be much more balancing (and make more sense) to go with the usual eye in the storm where the weather is calm.
Freeze AtmosphereEeeeeeevil.
A martial user of this stance playing it stealthy and readying an action each turn to move along their prey so that they always end their turn close to them would destroy anything just by being there.
Otherwise, you put 'Frostwind Virago' there when the maneuver isn't meant to be used only by that one specific race.
Lunatic HailstormOnly concern is that normally maneuvers aren't really supposed to be better than spells. This level 8 maneuver does the same thing as a level 8 spell and more.
I don't see why it should do more, especially when the power of a level 8 stance is around that of a constant level 4-5 spell.
Cold DivinityThere is no range indicator as up to how far these ice walls can be created. We assume it is the same range as the Wall of Ice spell but indicating it in the maneuver tags would be nice.
It feels like this stance isn't really a stance. It's more like an improved Frost Pillars maneuver, which wasn't a stance itself. The initiation is a fullround action as opposed to a stance's regular swift action and the target is not really 'you' since you are creating effects all around.
Perfect FreezeCompared to Desert Wind's Inferno Blast (and all the other ones, for that matter), this maneuver is absolutely overkill as far as damage goes.
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This is a powerful discipline, no mistakes. The feeling the maneuvers give me is that they were more designed to be a form of spellcasting using the martial system than an actual martial discipline. Most disciplines are axed around combat and enhancing battle prowess but this one has no 'battle' vibe to it. Like a spellcaster type, it mostly deals with battlefield control, buff/debuff and nuking scores of enemies without fear of running out of spells. It isn't really ranged "combat". However, I think that was the intended idea of the discipline and believe that the maneuvers available sets it in the right direction to pull it off.