I am not sure what 'PRC' in Sprint Focus means, but if it means, there is work done on it, I appreciate ... ;)
I am also not sure where to post, so I will post here, what my ideas about the feature were, when i thought about it the last few months.
You may reuse it as your own, I am not interested in winning laurels, I just want a working solution for all parties (and not at least: myself).
Status quo:
1. There are some people (like me) who use the feature a lot.
2. There are some people who do not like the complete idea of global extensions, and AFAICS their main argument against is, that the core-code gets 'poisoned' with external code. -> reasonable argument IMHO.
3. In 6.2 LTS the support for global extensions is weak (e.g. EM does not support installing or updating them!)
4. In 6.2 it is possible to symlink local extensions to other installations. With this feature you could somehow have a seperated installation just for maintaining the local extensions, and thus having them just one time for all T3 installations on one server. There are two 'sub-possibilities', either symlinking each extension seperately (what makes usage of new extensions a pain) or symlinking the whole local extension directory, but then you will lose the 'local' extension functionality, what is rather painful too.
Quo vadis:
To satisfy both sides, there would be a rather simple solution:
We may introduce a new path for 'global' extensions. The path could be e.g. typo3conf/extcentral/, or typo3conf/ext/centralext/ and this one could be symlinked completely.
We need some time to transform existing extension for proper path-usage, but if that time has gone, we could remove the old 'global' extension dir completely, without losing this very useful feature!
Maybe with path 'typo3conf/ext/centralext/', some extensions will just work out of the box (I did not test it yet!), if they just use stringently the API functions for calculating the correct extensionpath (which should IMHO be a hard-requirement for every 'cohiba' extension anyway).