A year ago, Google News started showing errors in Google Webmaster Tools named article too long. For these errors, Google would not include your article in Google News because it was too long.
Sounds a bit crazy, but I guess there is some logic to it. Articles that are too long may not be articles at all, they may be privacy policies and so on. It may be hard for Google to determine what is an article on a web site and what is not, so maybe length is a characteristic.
I recently spotted a thread at the Google News Help forum where Inbal, a Google News representative, said that they allowed one site to submit articles that would typically be flagged as too long.
Thanks for providing these examples for the "Article too long" error. I've updated your site's info. in our system to include more of your content in Google News.
So it seems that Google can make exceptions for some sites with this error message. If you see it happen often, reach out to Google in the forums.
Forum discussion at Google News Help.