For an automated system to do perfect typography it would have to not
- break a paragraph so that it's so poorly spaced as to be virtually unreadable.
- break a paragraph and introduce an incorrect hyphenation point (i.e., hyphenating present w/o knowing if it's the time, or a gift / verb form)
- not typeset any stacks or rivers. Every paper which I've ever read on H&J indicates that an effort to detect and prevent stacks results in race conditions and endless loops where a break which prevents a stack is removed and then re-inserted.
``Good enough'' isn't, and only perfection should be striven for.
Of course if one allows gappy paragraphs and disallows all hyphenation, a system can set a paragraph --- the problem is, that's not a well-set paragraph, nor is it good, or even mediocre typography.
Breaking paragraphs optimally, so that they are well-spaced, all hyphenations are linguistically correct and there are no rivers, or stacks is simply not perfectly automatable at this point in time. If nothing else, it requires the existence of a grammar checker with a perfect understanding of all forms of expression including idiom --- does anyone seriously believe that that exists now or is likely to w/o major advances in artificial intelligence?
I write typesetting systems for a living (
http://www.customstoryinc.com/ ). Believe me, I've been looking for better solutions for typography for a long while now and TeX is the state of the art, but can still require a lot of manual intervention.
William