I think a Shotgun version of the "Automator" app in Mac OS X would be an incredible addition. It would mean I could create custom templates for creating or modifying or deleting any number of any kind of entities with complex rules for how to fill out their fields or determine relationships, etc. A user could then run it as I created it, or modify it slightly to fit their immediate needs and then use it as a one-off.
I think this is a better overall solution than attempting to solve what is essentially the same problem over and over in specific ways, like a feature for creating multiple shots and using "task templates" to add tasks to them. And it's better than having to always write a special script outside of Shotgun to handle it.
This is something I always wanted to add to our system, but instead we have been fielding regular requests for what we call "wizards", which have been getting more and more complex and powerful in themselves, but are still not a unified solution, even though there is a lot of overlap in the logic and functionality. I really wish we had put the time in the beginning to write something like Automator that users themselves could create and customize and manage on their own.