I appologize in advance if this has already been suggested.
After having spent many months using WordPress at a professional level for both my customers and myself, I must say I really don't have much to complain about.
The only noticable annoyance on a daily basis is the fact that, very often, when I finish editing a post, I want to edit another and, instead of being able to click on that other post's Edit link directly, I have to click on "Posts" and then click on the Edit link of the other post.
This might seem like nothing to you, but I personnally play with many posts simultaneously and this becomes a relatively important annoyance on the long run.
If the list of the posts could appear somewhere in the left menu or anywhere else while on edit mode, that would be great.
Keep it up!
Ant, Lausanne, Switzerland