There is a new patch bundle, 8.12 available, I doubt if it will help you much.
There is no patch specifically for the GUI running on W 2012
We sometimes experience delays when starting the GUI because it is querying a large IDB, and again when using Devices and Media, or the Internal Database context
If you run the GUI on the same system as the Cell Manager, do you experience a similiar delay. If not, this may indicate some network performance issues
This business about taking 10 minutes to open a backup specification is very bothersome. All that is happening is that a ASCII file is being read. You probably need to think about opening a case for this