So first off, the new 10.3 License Geodatabase tool is pretty cool. One thing I noticed however is that while you can set an expiration for the Geodatabase and also prevent users from being able to export it, there's no way to control who can access it which would be hugely useful.
I have quite a few Desktop users and the way I control access to data now is by packaging it within a Python Addin and disabling the buttons on the addin to add data if a user is not authorized to see that data. However, if a user were savvy enough, they could certainly just go into the Addin Assembly Cache and access the data directly and I have no way to prevent this.
It would be really useful to be able to License the Geodatabase to certain users according to their Windows Login. That way, even if they were sending the data to people I don't want to see the data, those people still wouldn't be able to access the data.