WordPress Export Sucks and How to Fix It
Exporting data from Wordpress to take it almost anywhere else is a crapshoot as to how well the data will migrate. The extensible nature of Wordpress via plugins means you get an unknown assortment of data coming along with the base contents of your post, tags, and comments. If you didn't delete spam comments before your export, you get to bring your spam with you. The awesome Wordpress revision feature hobbles your export file with every revision and autosave you ever made. Depending on where you choose to move your data (I know, who would ever leave Wordpress, right?) you may be stuck cleaning the Export file in order to get your content properly installed anywhere else. I've even had the misfortune of having another Wordpress install barf on content importing because a plugin from the old install wasn't on the new install, which meant that the new WP install didn't know what to do with some improperly handled metadata.
Instead of just giving me a dump of all data when I click the Export tab, WordPress should walk through a little wizard asking me what I want to keep. Let me choose to leave spam and revisions behind. Let me choose to leave all comments behind (without deleting them from the database). Maybe my tagging skills we lousy in a past life and I want to make a fresh start, so give me the option to exclude tags. These are all easy features to include. Maybe that's asking for too much usability out of a free solution, but if it's really the ultimate content management solution (it's not), WordPress should be making it easier to work with data.
I know I'm going to hear that I should use plugins or develop these features myself. After all, WordPress is infinitely extensible. There is a plugin to delete revisions from WordPress. I don't want to need a plugin to get clean data out, because I have no way of knowing whether that plugin will actually be stable. This is core functionality that would make Wordpress more useful to me and anyone else who ever moves their data around. I just wish they would fix it!