I think it's going to be awhile till anything gets updated with this plugin as Shaun has his hands full getting one of his other plugins ready to be included in the next wordpress update (3.9). I have started to try and help out with development and have delete working both per item and bulk. I would love it if you would give it a try and let me know what you think. And just in case you are using tags for your media I have a different branch that has searching by media tags working as well. You will need to have either the Enhanced Media Library plugin or Paul Menards Media Tags plugin installed for this to work (for now).
If you are interested just download the new files from my fork on Github. Just click on Download ZIP on the right. Rename your original media-grid folder to something else so you can easily revert back and copy the new media-grid folder into your plugins folder.
Just Delete working: https://github.com/pauldowlin/wp-media-grid-view
Delete and search by media tags: https://github.com/pauldowlin/wp-media-grid-view/tree/media-grid-filter-by-tags