1. I'm not sure what you mean by drag-drop of images (we already have
drag-drop reordering of images in albums, and drag-drop uploading with
the upload applet)
2. tagging areas of images would be useful and has been often requested.
3. We're now using the piclens slideshow which will be included with
Gallery 2.3 (you can check out a nightly build or subversion to see!)
and likely won't accept a project to do another slideshow. Yes, we
know the ideas page needs to be updated.
-Chris