The new rage formula has been posted over on the official forums. if you like crunching numbers then this is a great thing for you!

The old rage formula averaged a Warrior's rage with 2.5 times weapon speed.

* Main hand hit: 2.5*speed
* Off hand hit: 1.25*speed
* Main hand crit: 5*speed
* Off hand crit: 2.5*speed

The change that occurred in the 2.0.10 patch increased the multiplier to 3.5 times weapon speed.

* Main hand hit: 3.5*speed
* Off hand hit: 1.75*speed
* Main hand crit: 7*speed
* Off hand crit: 3.5*speed

That is what was changed.

Rage Gained from dealing damage = ((Damage Dealt) / (Rage Conversion at Your Level) * 7.5 + (Weapon Speed * Factor))/2