Stop making significant changes to the UI!
Imagine everytime Microsoft produced a new version of Word, they changed everything how the basic features of the program function and where to find them. Since 1.5, this is what's been happening to WordPress.
I love WordPress. But I hate how I'm forced to learn whatever latest and greatest UI the developers have thought up of *this* time. I still have a 1.5 installation and it is *easy* to use -- everything you need is right there. The only significant improvement was adding an upload box to the "Write post" section. Which was fixed in the 2.0-2.2 release.
Then 2.5-2.6 decided it was time to move everything around. Great, thanks. A year later, and I'm still looking for common features, like how to upload an image (oh, there it is, a tiny icon buried in the writing interface!). And wondering why "Design" isn't a "Setting" and instead appears next to Write and Manage (things you do every day... hopefully you're not re-designing your site every day!).
Now for 2.7, we're being told everything needs to be moved around again. Wow. Instead of coming up with a bullet-proof MT import routine that actually works, we keep re-arranging the UI as though some designers simply have too much time on their hands.
I'm sorry, but I -- and I suspect many other long-time users of WordPress -- are tired of it. At least provide a checkbox that says, "Keep old UI" in the settings.
Upgrading to a new version of software shouldn't mean having to re-learn everything about how it's organized. Improvements should be incremental, especially in point releases. Not, "Hey, we haven't moved everything around yet again in a year, let's do that!"