TL;DR - enable functionality to drag a package or multiple packages into another package to nest them.
We use the Microsoft Deployment Toolkit to deploy Windows to new computers. We have custom applications in MDT that call PDQ packages during the computer deployment. If I'm deploying a new computer in MDT for Joe, in MDT, I'll choose to install PDQ Custom Applications 01, which (after Windows is installed) will kick off a corresponding PDQ package called Custom Applications 01. I'll then nest all of the PDQ packages that Joe will need on his computer into that package. It would make things so much faster if I could open the Custom Applications 01 PDQ package and then just drag a bunch of other PDQ packages into this one and have it nest each of them, instead of clicking "new step", "nested package", and then choose the package I want to nest, and then do the same thing over, and over, and over again because it will only let you nest one package at a time.