RigaMortus2 said:
No. Not because of the When using condition, but because of the weapon you selected condition.
No. Not because of the When using condition, but because of the weapon with which you are not proficient condition.
What about
when using a
flurry of blows? Surely the same logic must apply. I think the point Iku Rex is trying to make here is that these other two situations use identical language, but while one might want to suggest that the flurry of blows restriction applies to all attacks made in the round, one wouldn't want to suggest that the Improved Critical benefit applies to all attacks made in the round. And the correlate question is, isn't this inconsistent?
If "when using flurry of blows" means you flurry the entire round, then "when using the weapon you selected" must mean that you use the weapon you selected the entire round, regardless of your ability to make off-hand attacks, natural attacks, etc. So by this logic, Improved Critical forces a fighter who take IC: longsword, to fight with two longswords if he wants to do any two-weapon fighting, because he's "using a longsword," which applies to all his attacks during the round. Weirdly, that he's "using a longsword" might actually mean that his light off-hand weapon transmogrifies into a longsword in order to satisfy the logic of the feat, when read in this way.
I read "when using flurry of blows" as meaning "when making flurry of blows attacks". I don't see any problem of consistency with Whirlwind Attack under this reading, because with Whirlwind Attack you "give up your regular attacks," when making a full-attack action, which covers your iterative, off-hand, and natural attacks for the remainder of your round, and you "forfeit" any other attacks you might have got from another source. While you forfeit the actions only while you "use the Whirlwind Attack feat," they are then forfeited. You can't forfeit something and then unforfeit it afterward. It seems nicely consistent and rules-agreeable to me.
edit:
And also, if you somehow get a 3.0-style haste effect (by being a choker, or something), you can spend your extra standard action to make a single attack after whirling. To use the feat, you give up your regular attacks when you use the full attack action. But afterward, you have the ability to use your regular attacks again. Of course, you don't have any more actions, unless you get an extra action from said haste effect, and you may then make an attack using one of your regular attacks (whichever would be legal to make using a standard action). If we are to read as others have suggested, that once you are using a feat or ability (in this case, the full attack action), you count as using it for the rest of the round, you couldn't make that attack using the extra standard action, because you're still "using the full attack action" and are still giving up your other attacks.