[Update: and now there's a fifth discussion thread, which you should probably use in preference to this one. Later update: and a sixth -- in the discussion section, which is where these threads are living for now on. Also: tag for HP threads in the main section, and tag for HP threads in the discussion section.]
The third discussion thread is above 500 comments now, just like the others, so it's time for a new one. Predecessors: one, two, three. For anyone who's been on Mars and doesn't know what this is about: it's Eliezer's remarkable Harry Potter fanfic.
Spoiler warning and helpful suggestion (copied from those in the earlier threads):
Spoiler Warning: this thread contains unrot13'd spoilers for Harry Potter and the Methods of Rationality up to the current chapter and for the original Harry Potter series. Please continue to use rot13 for spoilers to other works of fiction, or if you have insider knowledge of future chapters of Harry Potter and the Methods of Rationality.
A suggestion: mention at the top of your comment which chapter you're commenting on, or what chapter you're up to, so that people can understand the context of your comment even after more chapters have been posted. This can also help people avoid reading spoilers for a new chapter before they realize that there is a new chapter.
I've thought about this a bit. Emotionally, I agree with you. But all the counter-arguments make sense. I've finally narrowed it down to a single sentence, at the end of Chapter 54:
This sentence is epic. It sent shivers down my spine when I first read it. It resounds with finality. The jig is up. The battle has been lost. Despair, all ye mighty. I couldn't wait for the next installment to find Harry waking up in an holding cell with his plans crumbling about him, desperately thinking his way out of this jam without giving up his friend.
Now, I do actually enjoy the next two chapters. But the promise of finality was broken. Ch55 starts out with "And then it was already too late... PSYCH! It's not too late at all!" It feels like the X-men comic books I'd read as a kid, which on the cover showed our heroes dead or mortally wounded, the villain of the month triumphant above them, but when you grab the comic and read it you find that nothing like that happens in the story.
If that line was removed (or at least changed to not be so Final) the transition between 54 and 55 wouldn't be jarring.
Prisoner's Dilemma, huh? :-) I had the same hopes for 55. Right now it looks like Harry will escape the mess without losing anything. Whyyy? Corwin of Amber had a spectacular failure that got him imprisoned and blinded, and the story was better for it.