This is an error I reported about Oct 2010, I've been brushed off by support, it seems there are no plans at all to fix it.
Export WP blog to xml, selecting all options.
Open new WP blog, import xml, selecting all options.
New WP blog should be identical to old
* post featured image - not preserved, deleted
* gallery image captions - not preserved, deleted
* gallery image alt text, etc - not preserved, reset to post title (not slug)
* gallery image order - randomized
* gallery images are doubled. a post with 1 image will become a post with 2 images. however as above the order is randomized making it impossible to manually delete half the images
* inline images - randomly linked to old post - see testsinglepost.wordpress.com/2011/03/20/test-post-for-transfer/
the inline image points to the original link. strangely the alt text is preserved here.
* Note that in the media library, all the new images are now named "Test post for transfer", making sorting or searching impossible
* links to other posts are also randomly linked to old post or changed to the new, there is no way to predict which it will be.
As a programmer myself, 80% of these look like simple fixes, it shouldn't take someone working on the code more than 2 days to fix them up. As a person who has waited for over 6mths, I've considered hand editing everything from scratch, but deleting half of 2000photos and reordering/recaptioning them sounds stupid even for me.
After a few mails with support, they introduced the domain name change feature. However this also had a few of the same issues, and after a few tests I wasn't confident enough to risk losing any data to a one-way operation.
Also, the domain name change does not allow you to move to a WP.com name that you already own, which rules out everyone who tried the import already and found it broken.
The blog I need help with is iliodos.wordpress.com.