Take advantage of enhanced AppleScript and Automator support: operate on image selections (in addition to projects and albums); filter for the "pick" of each stack; automate the export of master files with associated XMP metadata.
Whether you call it AppleScript or Automation, it seems that Apple is at long last embracing automation in its Pro applications, or more precisely procedural automation. The distinction is important, as Apple has, via increased use of XML as its base file format in more and more applications, increased its use of file automation.
XML allows you to automate a great many processes since the format is reasonably open and able to be modified with relative ease. However, that doesn't automate the process of creating the XML. Yes, you can create most XML in almost anything, but as the XML gets more complex, creating files outside of their "normal" application can get more difficult until it's not worth the effort.
What AppleScript does is let you automate the procedures that create the final output, or really, any procedures supported by the application's scripting implementation or dictionary. AppleScript is the default language for Apple's Open Scripting Architecture, or OSA, which is the framework behind inter-application automation at the Cocoa/Carbon level in Mac OS X.
To illustrate how critical AppleScript has been to Apple, it is not much of an exaageration to say that Quark Xpress, and the massive amount of AppleScript workflow saved Apple's bacon in the publishing industry during the mid to late '90s.
However, Apple has always had a very fractured attitude toward AppleScript. A few years ago, it was pretty bad. At one point, Apple only had two non-OS applications that supported AppleScript, or were scriptable. This rapidly got better on the consumer side, and is one of the reasons that iLife applications work so well together.
On the Pro side though, the answer was usually a variation of "You can't automate creativity," to which the reply was "Even a Final Cut artiste does a lot of monkey work." It seemed that Apple's Pro applications teams were simply never going to understand the importance of AppleScript, even though other "creative" application vendors, like Adobe, had learned this lesson starting around Photoshop 6 or so.