Booklet creation El Capitan
I found a method that works for me. In this thread (https://discussions.apple.com/thread/7253885) I discovered that you can create a print plugin in Automator that will do close to what you want. 

Go to Automator and first create a new print plugin. 

Next search for Rename PDF Documents and add-drag that into the workflow. You will not actually need to change anything or use the rename tool. It was what fixed the problem in the other thread.

Last search for Create Booklet and add-drag that below the rename section. 

Finally save the print plugin. 

It should allow you to go through the PDF menu on the print dialog and allow you to create a booklet on the Desktop. You'll just have to go through the extra step to open it and and print it out. 

Hope it helps. 

The whole print plugin should look like this: