Stat penalties were (IMO, of course) one of those 3e-isms that looked good on paper but ground the game to a screeching halt. I can't tell you how many times combat was held up as a player or the DM has to recalculate half a dozen numbers--attack rolls, damage rolls, skills, saves, whatever--because someone dealt Strength or Con damage.
My hope is that 4E--not just the core rules, but for the life of the edition--does away with such things utterly, and conveys similar weakening effects through static penalties (i.e. -2 to all attacks, or half damage on all attacks) without worrying about specific ability modifiers.