I have one and only one request:
Make WordPress less a pain in the butt when moving databases from one server and/or domain to another. I find it really cumbersome to search and replace absolute URI links and server Unix paths within WordPress databases every time I shift hosts.
Why can't site root URI and Unix path be defined in one location only? Defining them in wp-config.php is a good start.
For the most part, I develop on my localhost, then end up uploading the finished product to my client's host. Often I find myself downloading databases from my client's hosts for debugging and backup purposes, but each and every time I have to hack the databases for the aforementioned reasons.
It would be nice if future releases of WordPress would put this nonsense to an end, in fact I was hoping this would be fixed in v2.5.
Anyway, WordPress is a really nice CMS. My clients love em and I like working with it, and I hope future releases will be more friendly with moving house.