"Deploy to a specific" field should be an dialog with a list of servers
"Deploy to a specific subset of machines" field should be an dialog with a list of servers and checkboxes. You should be able to "Select All/None".
It will cover the cases when you have environment with many machines where you need to install all except one/two.
Now, you need to select it one by one, which may be pretty annoying when dealing with environment of dozens servers.
It does exists in some competitors products.
Agreed, its a must.....