I haven't tried Storm of Vengeance yet, but that barracks may be a poor test for its usefulness. Those guys in the barracks are fodder. I sent Minsc, and Sarevok in, both charging with Whirlwind, and the room was just a bloody mess after a few rounds. Just a bunch of weak orcs and an orog or two. Any area-effect spell would have wasted them (wilting, dragons breath, comet...)
Still, I'll pick Storm for Viconia next time and check it out
