A really nice feature to see in Fences would be making the fences retractable and expandable.
Now I know that you can double click to hide them.
And I know you can choose which will not be hidden.
But it would be neat i.e. to have the fence's title and click on it, and it would expand and show it's contents, then another click to hide them.
I think this feature would mostly be helping to users with small monitors on which the desktop would still be a bit cramped even if using Fences already.