Well, steering and brakes is a little extreme. I use both of those every day. But of the 24 active Silverstripe sites I have, none of them have ever used the move files feature, and again, it's the first I've heard of it. On the other hand, there is no shortage of clients who continually ring my phone about the archaic 200-click process of setting up an upload queue in AssetAdmin. So it's more of a "squeaky wheel getting the grease" type of situation -- to continue with the automotive metaphors. :)
I do intend to keep upgrading it, however, and I hope I'm able to accommodate the move files feature. In the meantime, users who miss that feature can turn off the override. For now, I'm happy to have given clients a more competitive uploading interface that saves them a lot of time.
I like the idea for multiple deletes. The problem with adding that feature to DOM so far has been the conflict of checkboxes in RelationDataObjectManager. What does clicking a checkbox do? Assign a relation or queue it for delete? Or do you have two checkboxes? Confusing!
But in the AssetManager, there is no question of relation, so I could pretty easily add that in.