Literature/Headscratchers/The Seven Per Cent Solution

The entire premise of this books bugs me. Supposedly a Retcon of the Final Problem, this has Watson saying that he essentially spared Sherlock Holmes's blushes and his cocaine addiction by libelling a relatively innocent maths professor as a murderer and organiser of all the criminal activity in London. How did Watson not have his arse sued off him by Moriarty?
 * Names changed to protect the innocent? And then not changed back so Watson's readers would remember who he was talking about.
 * It's just a Fix Fic. Would it be reasonable to expect making prefect sense from a Fixer Sue + Possession Sue fic built around two messages brought by the prevailing political winds? And done not just by anyone, but an author from the show most famous for exploding consoles and variety of plot-driven goof. Seriously, i'd be amazed if all ends were neatly tied.

(no subject)
In Nicholas Meyer's derivative The Seven-Per-Cent Solution it transpires that the real Professor Moriarty is (relatively) innocent and being persecuted by Holmes while the latter is blitzed on cocaine; Moriarty proceeds to complain to Watson about this, and threatens to sue. It's also said that "The Final Problem" was made up by Watson to cover for Holmes's absence. But that story would then perpetuate the slander - wouldn't being described as a "Napoleon of crime" in print make Moriarty even more annoyed? (Or for that matter, the letter-writing brother he has in "The Final Problem"...) To say nothing of the ethical implications. Why couldn't Watson at least switch his rather distinctive name?
 * Perhaps he did change the name... and kept the name change in the "real" account of "The Seven-Per-Cent Solution." Also, I feel it's worth noting that in the book, the worst thing Moriarty did was try to teach the Holmes brothers calculus. The Movie just changed it to give Holmes a better reason to hate the guy.
 * Well, in the novel, Watson believes that Moriarty is somehow more involved in the events surrounding Holmes' mother's murder than Freud thinks (given Mycroft's hold over him). So perhaps whatever this hold was, it also kept Moriarty's mouth shut over the "slander."
 * In the movie, Holmes says something to the effect of, "Tell them I was killed by my old math tutor! They'll never believe you."
 * Watson transcribed the novel while retired in an old-age home, after having promised Holmes that he wouldn't publish the story until Freud had died. Moriarty was elderly in the novel; I'm certain he would have died much earlier.
 * Except that The Seven Percent Solution is the novel that exonerates Moriarty, so, um, nevermind.