Lots of people hit straight irons (or even draws) and slice their driver. The longer club is a little tougher to turn the ball over with and overswinging the big dog leads people to cut across the ball or leave the face open because of the timing issues that overswinging creates. Offset drivers or clubs with closed faces are a crutch. If you really want help hitting the ball straight (in terms of a hardware solution), I'd suggest a draw-biased weight scheme over an offset club or a club with a closed face angle.