Yeah I just read the letter too. The thing is, that despite Eszterhas's claim to otherwise, it's clearly a letter meant to be read by people other than Mel Gibson. I also can't see or understand Eszterhas continuing to work on this project if half the things he says are true either.
Oh, absolutely, he obviously meant to leak it.
I also found that weird, that he didn't quite the first time Gibson allegedly started talking about "the Hebes"... he kind of answers that, saying he was hoping the "power of the story" would win Gibson over, and obviously he was very attached to the story. Vanity or the difficulty of getting out of a contract might also be reasons. Still, it seems more than a little weird that he kept working with Gibson if everything he says is true.
...I think this story should be a movie on its own, really. Maybe one done by the Cohens. Starring Mel Gibson.