I wish that the list in the Weblogs drawer was really a tree. Once you get more than one blog in there (or even just one blog and a drafts folder), it's pretty easy to mix up which blog list you're looking at in the main panel. It's really bad if you have similarly-named blog entries in the different blogs. The current setup, with visually disconnected views, is too similar to Windows Explorer.
With the hierarchy handled by the Weblogs panel, the main window would only have to show the currently selected blog entry; the upper list could go away.
Of course, wiht this new arrangement closing the Weblogs drawer would make it even harder to know what you're editing. So the Weblogs panel should probably be more permanently positioned in the main window.
Perhaps the current setup could be an alternate view used when you only have one blog?