One thing I'd love to see in future versions of wordpress is a more 'responsive' "add media" area. Once I've already uploaded 5 attachments... wordpress should assume that I want to view my gallery the next time I open the image box. Otherwise, it is alot of extra clicks to individually add all my media to the post area.
Additionally, the gallery feature could be improved to exempt certain images as well. For example, I'd love to upload 10 images... use one for a video preview... and the other 9 inline in the post. I can't easily do this because the gallery functionality automatically grabs EVERY image associated with the post.