Just dropping in to point out that the very first responce referenced both history and realism in order to denounce this suggestion.
Other people have done similarly. Die.
Just unfuck throwing. I do agree, however, that spear and shield sucks. It will always suck if the ~30% penalty to speed (and damage?) remains in effect. It will certainly suck so long as its users may only attack in one direction. If you wish to throw, use the throwing lance or throwing spear (not sure how these work with shield, though).
Someone with two war spears would get a free throwing weapon, not sure if bad.