Who are you referring to as the best Irelia in NA? I went and checked Irelia Carries U (the D1/Challenger Irelia main I know of) because those masteries didn't seem right, and he uses Expose Weakness/Spell Weaving/Blade Weaving instead of that 1 point in Fury/Feast/Frenzy, which makes more sense to me.
He changes his masteries quite often, he was using the ones i had listed the last time i actually checked, but that was when he was still using the name bronze 5 irelia