I am a huge WP lover. I use it on almost all of the sites I build and I think that it makes a great CMS. However, I have encountered a few situations where the end user just is not savvy enough to use even the WordPress backend.
So, I set out on another painstaking quest to find an easier to use CMS. And I in fact found one. Concrete 5. The reason it's easier to use is how easy it is for content editor to make changes to the site. They simply log in then go to the page they want to edit, click edit page on a toolbar at the top of the page and then click the area they want to edit and a WYSIWYG editor pops up. I have simply not seen an easier want to edit a website.
My request is this, the ability to edit content inline. If a bar were to appear at the top of the page (like the one that shows up on wp.com) that had the option to edit the current page or add a page it would make WP by far the easiest CMS/Blogging software ever made. Then for those times when the people using the site truly are not capable of using the backend, you would simply use one of the plugins to hide most of the backend to them and let them deal with the easy to use inline editing.
Another function that would be helpful and that would tie into this would be the ability to add little content blocks that are not pages or post. So for instance, I use two sidebars to make the left and right sides of the footers editable but if there was another built in mechanism to add editable text to the page it would be tremendously helpful.
Just some thoughts I had for future features or plugins. If only I knew how to do any of this!