Faster connections to ArcSDE geodatabases, by connecting 1 time and reusing the connection from cache.
When you want you could click the "Refresh connection" button to see new content, or other changes made in the geodatabase structures (new/renamed/deleted Feature Datasets/Classes, Tables, Rasters, etc.).
This would be a vast improvement for those of us who have to work with ArcSDE in ArcMap. Today every time you connect to ArcSDE you have to wait 1 full minute before you see its contents and are able to select what you want to load into your map. If you cached the contents of the geodatabase, you would only wait the first time.