Thanks for the kind words about SP. Regarding your questions...
1) Date sorting across feeds has been requested a lot. :-) The concern we have with it is that by breaking up a feed and intermixing the articles with other feeds, the integrity and cohesiveness of the feed as a publisher has provided it will have been removed. The feed content and articles are copyright of the feed publisher. Intermixing feed articles with those from another feed might violate the copyright of the feed publisher. This is why we have not implemented date based sorting across feeds.
2) We are actually working the author feature this week and almost done. Can you post a feed url that has the author for each article in it? A feed with authors and their pics would be excellent to test with.