I am very excited about the potential for a platform that encourages opensource collaboration on LabVIEW code.
My main experience of non LabVIEW package managers is with NPM for Node.js. NPM is an organisation which provides two things - a tool which is the mechanism for managing what packages are used in a project and a registry that allows for anyone to publish their packages to.
I believe that NPM supports private packages for enterprise customers but open source packages are generally hosted on github and when a package is uploaded to the NPM registry it simply pulls in the README to provide the package documentation. The github link is also provided on the NPM page so that users can easily see where the library comes from and if they want to open issues or submit fixes then they do that on github.
I have not had much of a chance to look at it but it appears like GPM would/does follow similar mechanics to NPM and compared to VIPM and NIPM I am certainly most excited about the GPM model.
I see GCentral as a organisation that could provide the registry for packages and ideally be the one place for opensource LabVIEW code (including NI-community page hosted code) with clear signposts as to where to find the source for issue raising and forking.
One issue that many text based languages don't have is that users with older versions of labVIEW cannot even open code made with newer versions of LabVIEW, let alone run it - so maybe GCentral could provide some computing power (and licences) to automatically convert VIs to older versions - even if they didn't run, at least a user could open them.