I have been working with VS2015 and Nuget 3.0 for a few weeks now and I am not sure the new UI us a real improvement. On the positive side, I like a lot of the new features (especially the easy way to pick a version to install). On the negative side, I
really miss the hierarchical view of my projects and how the packages were installed. With large, complex project that use solution folders it was much easier to manage installs and upgrades to "groups" of projects at once. As an example, consider
needing to upgrade something like Catel or Xamarin.Forms. In the old UI, I could manage the packages at the solution level, select everything under the solution folder "Application" for an upgrade and be done (or I could remove and reinstall if needed).
Now I have to depend on naming conventions to easily select/deselect or worse I need to mange on a per project basis (when you have around 15 to 20 projects this gets very very tedious).
Please consider bringing back at least the tree view of projects.