Before everyone jumps on me for talking about fictional characters, just think on it, why only rangers, why not a two-weapon fighting fighter or rogue? Seems to me the guys who wrote the new rules didn't think on it very well, just my opinion on the matter, changing a pretty cool fighting style that other classes could have in older versions to only one class having or another mutli-classing into and not getting their other cool "powers".
You can be a two weapon fighting rogue. In fact almost every rogue in the game is likely to take two weapon fighting feats and fight with a weapon in each hand.
What you can't be (easily) is a rogue who attacks twice as often as normal. But that's not remotely the same thing as not being able to be a two weapon fighter.
I just wish they had made the two weapon fighting a strength or dexterity based skill, so it would be valid for multiclassing rogues to take it.
If they had made it strength or dex, then bow rangers would fight in melee almost as well as they shoot.