Sorry about the lack of communication on this one, it wasn't assigned to one of The Team that monitors the forum, so it went unnoticed. Our bad.
So we totally agree that you have a right to complain about this one because it's something that we know is frustrating. We know making bulk changes is time-consuming currently. We really want to improve this, but this first involves making the Dashboard easier to work on for our development team.
The Dashboard was built with an internal language, so we are now in the process of modernizing our technology stack that way we can more quickly make changes like this. Once this is done we'll have more bandwidth to work on features like bulk media deletion. This could involve rebuilding the media library from the ground up and could include features like folders and improved search. So given all that I don't have any ETA on this.
We will be releasing bulk actions for documents in the near future though which was our first priority. So we hear you and we are working hard to meet your expectations.
Thank you for your patience and understanding.