I think the balance between the TWF and S&B Fighters in 4E was pretty solid. The S&B had better AC (and Reflex) and thematic attacks like Tide of Iron. TWF did more damage and had different thematic attacks, though didn't get two attacks every round like the Ranger with Twin Strike.Also in 4e, the TWF was split between the fighter and ranger. The TWF ranger was all offense and mobility but lacked a challenge. The TWF fighter was defensive but couldn't not focus both attacks on a single target easily and didn't wear plate. Therefore a W&S fighter in 4E had way more AC than the TWF fighter for only a small loss in offense.