If only they'd fix the way, when you add a new keyword tag, it jumps higher up in the scroll window, forcing you to scroll back down to be able to drag pictures onto that tag.
Or when you try to drag photos to a keyword tag that's above or below the currently-displayed stuff on the left bar, sometimes it'll scroll up or down, and other times it refuses.
Or the way hidden sidebars sometimes keep popping back up.
Don't get me wrong, I still love Lightroom, but I really wish they'd fix some of these incredibly basic usability issues that have been there since 1.0. (OK, I'm still on 1.2, but I'll be surprised if they fixed those.)