There's no such thing as "great unmaintained code".

of course there is... great code that doesnt get refactored. Kick aside corporate jargon and namby-pamby ness :)

The point was sometimes stuff just works, much better than a mess of a refactored project that has a core flaw.

Great code is still subject to entropy. Shit will break. Mail servers will start using some proposed SMTP extension, someone will find a nasty bug or two, there will be security problems and inconsistencies and inefficiencies discovered.

Sure. Then you simply require hit-and-run commits to be well-commented and also include good docs.

Just because it's not currently maintained does not mean it won't be maintained in the future.

What set of fatal flaws are you talking about?

huh? what? the flaws in XYZ piece of code.

(I think your misunderstanding: I was replying to the generalisation with a generalisation)