I was working on a little proof of concept for an integration between different social platforms and SiteCatalyst. In this case, I had to build a simple web application that will give the user to specify certain pieces of data they want to track across social platforms and a watchdog of sorts to monitor those social platforms for the data the user specified. Rather than building this as a one-off application that sits on it's own, I'd love the capability to build this type of functionality directly into SiteCatalyst. Facebook is a good example of a platform where users can create whatever type of application they want and build it into their platform.
I would also like to integrate into the Omniture product ecosystem to extend functionality that isn't there. For example, the notes functionality for reports is pretty basic the way it is today--AFAIK, all you can do is add a simple note to a report. I'd love to have a timeline of events that happen both online and offline that could affect site traffic... that way when upper management is looking at a report, I can lay my timeline of events over any given report to see how the data in SiteCatalyst is affected by the events. (Maybe there's a way to do this kind of thing with the notes today--I don't know. It was just an example.) These two things are related to a certain extent, I know. Creating a development API to extend the functionality of the Omniture suite could be an amazing thing both for Omniture and customers--with other products that have capabilities like that, marketplaces open where developers can create, share, and sell applications created for the platform attracting more users and developers.