Uncle Cheese,
I was wondering if you wanted to pass the maintaining of DOM to some of the community. I have seen many bugs creeping into it as SS changes (not that your code is buggy but as SS changed not everything has been completely updated yet). There are numerous posts regarding different common problems and many of us are implementing fixes on our own sites. I now have to keep my own distribution that has many of the fixes in it as the versions available via Git are no longer useable. I would be happy to do what I can to put my own fixes in as I make and test them.
One such update that should be made to trunk is in this post http://www.silverstripe.org/dataobjectmanager-module-forum/show/15732 by aleks. I have been making this change myself for a while now.
Another one is the Folder creation problems people have been having. This is the post where I submitted what is my work in progress fix that is actually working pretty good. http://www.silverstripe.org/dataobjectmanager-module-forum/show/15155#post305877
I have also noticed that FileDataObjectManager creates the Assets folder inside the existing Assets folder if the $GalleryImageManager->setUploadFolder($uploadfolder) function is used to set the upload folder instead of the dropdown. I am sure many of us would like to see our fixes implemented as we must for a time still build new websites with SS 2.4.5 while waiting for SS 3.0