I'm not sure you will find a definitive answer. There are a lot of trade-offs.
Long page are good for printing and searching, short pages are good for reference.
Good site maps and UI can make both long and short pages very usable or very annoying. A clear understanding of the content and USE of the content is critical. The maintenance issue is also critical. It seems to get lost in the quest for the perfect interface. If the site gets stale, the best UI in the world won't bring people to use old information.