Hmm, thought I remembered something about it lowering RT for the one strike and delivering some crazy good damage...but here's what I find..
Whirlwind Attack [selective, WHIRLWIND command]
A specialized technique for delivering a massive attack with
incredible damage.
guage warrior
You are well above the Draconian warrior's general combat level.
You jab your adamantine longsword at the warrior and land a good strike.
You jab your platinum-hilted longsword at the warrior and land an awesome strike.
[You feel very weak, are completely rested, in an excellent position, and are excellently balanced.]
[The warrior looks to be mildly wounded.]
[Roundtime: 2 seconds]
>whirl war
You clutch your longsword tightly before unleashing all of your fury in a powerful whirlwind attack against the Draconian warrior!
The warrior appears a bit dazed by the attack.
[Roundtime: 4 seconds]
>
* A Draconian warrior rakes his claws at you. You attempt to dodge but fail as the warrior scratches you across your left leg, just grazing you and leaving a slight sting.
[You feel pain with every breath, are completely rested, in an excellent position, and are excellently balanced.]
[The warrior looks to be moderately wounded.]
>jab
...wait 2 seconds.
So...really it didn't stun for more then 2 seconds, delt about the same damage as a normal attack, and added 2 second RT. Not sure if this is what whirlwind is going for as a final result, but being well over the critters level I'd hope I could do a little more then that...not sure though, we'll see how the upgraded whirlwind effects 'em later.