Your feed is OK, except that most of your episodes do not have 'guid' tags, and your enclosure tags are missing the 'length' attribute which should show the file size in bytes. Neither of these is serious and they would not cause a problem.
The Store does go through slow patches sometimes: there have been numerous occasions when people have complained about not seeing updates for two or three weeks, and I'm afraid that you've probably just hit one of these. There isn't really anything you can do about it. You could try emailing them at podcasts 'at' apple.com, but frankly you are likely to get a form answer telling you how to add episodes (which you already know). I'm afraid that it's just a question of waiting.
Thanks so much for the response, Roger. I knew that my older podcasts were missing the length and guid tags, and due to time, I made the choice not to go back and add them at this time. All new items going forward have those tags.
Do you think the slow patch is the reason the Podcast Cover Image isn't appearing?