Though the stolen base, itself, is over rated, the effects of speed on the game iss not. However, one of the arguements in favor of additional speed is the the value of it when on defense. In this case, Cedeno, it does not apply because he is such a terrible defensive outfielder.
On other point I'd like to make. If RISKING an out for a base, via the stolen base attempt, is considered bad baseball, then what do you consider SACRIFICING an out for a base, via the sacifice bunt?