There should be some way of seeing which posts and pages the image is used in from the Media Library screen. If the image is renamed or deleted, at a minimum the user should be warned that the related posts will be affected. Going further, an option could be given to automatically update the Markdown image tag in the related post when a renaming takes place.
It would also be nice to have the option to change the location where the image is saved so that we can have smaller image namespaces (thus reducing the likelihood of the -2 -3 problem occurring). Currently images are located at domain.com/content/images/year/month/image.jpg, where year and month reflect the time that the image was first uploaded. However, from a users perspective, I’m more interested in seeing the image URL match the publish date and name of the article or the name of the page, e.g. domain.com/year/month/day/post-name/image.jpg or domain.com/page-name/image.jpg unless the image is intended to be shared across multiple posts. More often than not images don’t need to be shared between posts, yet they’re scoped using a shared namespace.