Wow, cool skill. Looking at this from a competitive gamer point of view, I'd say that my skill is good for removing annoying encounters with slimes and shrooms that I don't want to bother rolling for, in case I end up getting really unlucky. Yours, on the other hand, is most certainly a boss killer. Bringing a boss' defence down to zero will net you a much easier win, there.
There's a metagame to every game, and I'm determined to figure out this one's. ^_^
EDIT: Actually, now that I look back, my skill could also be used as a Tank Buster skill. Meaning, a skill specifically designed to punish opponents that have high defence but low other stats, like HP. It would be cool if SMAC went Rogue, for the speed, and he ended up getting a skill somewhere along the lines that allowed him to attack roll twice in one turn. Double-Sword FTW. ^_^