Yes. There is only so much one man can take, and Tenet has reached his limit.
Bush has stood by Tenet throughout a very difficult time, but the DCI is still a mortal man, and his burdens are many.
Bush says he's sorry to see Tenet go, and I believe him.
We can speculate about what the straw was that broke the camel's back, but the truth is that they all did. He just doesn't want the job anymore.
Tenet has decided to throw in the towel, and frankly, I think that's about all there is to this.
No. There simply MUST be more. Because there's a 24-hour news cycle, and they are getting bored with Kobe, Scott, and Abu Gahrib. There are only SO MANY months a newsperson can cover those subjects without going, well, insane. Ask dan rather.