Stormguard Warrior is an excellent feat – for building a character around

Stormguard Warrior can add huge amounts of attack and damage bonuses, but it requires that you be pretty dedicated towards generating attacks of opportunity to not take. Specifically, the feats Karmic StrikeCWar and Robilar’s GambitPHB2 are often used, because these feats allow you to take many more attacks of opportunity than you could otherwise (Karmic Strike allows you an AoO every time you’re hit, while Robilar’s Gambit allows you an AoO every time you’re attacked, whether they hit or not). Other ways of getting attacks of opportunity (defensive rebuke Devoted Spirit boostToB) or prevents others from avoiding them (thicket of blades stanceToB as mentioned, Mage Slayer featCArc) are also useful, but don’t add nearly as much as Karmic and/or Robilar’s.

But Ironheart Aura is pretty much a dead feat, yes, and without Karmic or Robilar’s, you’ll rarely see more than +4/+4 from Stormguard Warrior. +4/+4 for two feats isn’t entirely awful, of course; the Weapon Focus/Specialization line (which are awful) is four feats for +2/+4. If you have reach and thicket of blades, the +4/+4 seems pretty likely; using defensive rebuke can improve that dramatically. And it is pretty much expected that you’re using Power Attack with a big two-hander, so it’s really +0/+12. Basically, you’re trading extra attacks (attacks of opportunity) for more potent attacks in general (skip one AoO, get a full attack with +12 on each attack). So it’s not a terrible use of feats. Just not the highly-recommended one that it would be with Karmic and/or Robilar’s.

Also, note the Combat Rhythm option on Stormguard Warrior; it’s not nearly as explosive as Channel the Storm, but it is cool. Personally, I have always wanted to have that opportunity to combine it with avalanche of blades for hilarity. That’s not really an option for a crusader with a warblade dip, though.

The other thing to point out about Stormguard Warrior is that the Evasive Reflexes featToB uses the same “don’t take an AoO you could have, get something instead” mechanic, and like Stormguard Warrior, it doesn’t use up the AoO. You can use both Evasive Reflexes and Stormguard Warrior. This is particularly useful when you have thicket of blades – their 5-ft. steps provoke an AoO from you, which lets you 5-ft. step to keep up with them and gives you +4/+4. If that step was to try to get away from you so they could do something that provokes (say, cast a spell while you have Mage Slayer, or attack an ally after you hit them with defensive rebuke), you have either just prevented them from doing that, or are going to get pumped up even more.

Is Stormguard Warrior really that good?
Please forgive me in case my question wouldn't make much sense. I was reading about ABO blood groups on Wikipedia, where I learnt that O is a recessive allele, and that it seems the A allele predates the O allele. My question is, therefore, how is it possible that almost half of the human population is group O?

For instance, I would expect (quite naively I reckon), if only alleles A and O existed, that around 75% of the population should be A, and 25% should be O.
