I magine that you have over 100 projects in you QC DB. And you have implimented this really cool customization feature in one project. Remember that you customization has both UI element and scripting sides to it. So the big dilemma is why would you want to repeat the same change in all of your projects? You gotta recreate all you IU elements and scripts... I mean you could copy and paste but what if there were even more than 100. So the BIG question is how can we propagate the chanage to all the other projects without having to go into all the project.
I don't have first hand experience, but do know of someone who has used ES to customize situations like you mention, where the core functionality is pulled down from a central space and then room to do specific customizations.