Yeah, dual wielding is better against goblins and kobolds and other small beans, but after that brief window at low levels, its no longer applicable. You may overkill by more, but you'll also kill sooner. If the game had minions like in 4th ed, dual wielding might be more useful. Ironically enough, of the 3 editions I know of, 3.5, 4th and 5th, 4th ed, the ones whose mechanics most lent themselves towards giving dual weapon fighting a use, was the only one where wielding two weapons didn't give you an extra attack.