If this hasn't been suggested, i will be extremely surprised.
It would be nice to have the main ADS be able to move instances around in the interface, i know we can always just directly connect to it, but its such a hassle since the people who need to connect to my main ADS get confused sometimes.
Something like "Instance Folders" would be nice to add, since for people like me that have multiple minecraft networks under the same organization name and we are going to expand to different games soon, so being able to easily move the instances to a folder (kind of like a desktop) would be a great experience. If that does get added, the ability to lock folders using the role/user permissions would be amazing, it would make it so you can add more users to the main ADS without worrying about high security risks.
I know there are better things you can be adding, but that would help out especially with release of the enterprise license (Whenever that's coming lol)