Ha! I figured WB would be the ones to move.
Gotta say, I love the confidence Marvel is showing in TWS by announcing its sequel before it even debuts.
They must be feeling really good about it.
It's not uncommon
And Sony did they with "Amazing Spider-man" too
It's a mix of "confidence" and striking while the iron's hot.
Ofcourse "Green Lantern" also announced a sequel even before the first movie debuted
Marvel has real confidence in what the Russo brothers brought to the table for "Captain America 2"