It was 4-5 years ago.. Madden '08 or '09 I believe. It was a part of the Superstar mode. This "defensive camera" is the same exact camera as that mode used. It's the same camera as the defensive lock camera from NCAA.
The ability to switch players with it is definitely new. But the actual view has been a part of NCAA for years and was in Madden before. Of that, I am 100% positive.
Don't get me wrong, I'm extremely excited it's in and I will use it exclusively while playing defense. I just thought it was comical that Rex said it was the first time in Madden franchise history that this camera has been available.
EDIT: Here we go.. Madden '07 had the Superstar Cam:
http://www.gamespot.com/articles/mad.../1100-6154796/