Actually registration is open to everyone now by
simple form
submission. So actually, any one developer could get any change they
wanted merged. All they need to do is trivially register a second
labs account.
Okay, but current situation is also a problem, because with it
reviewing and merging takes much more time.
And as I've said, I think most extensions aren't as important as the
core, and limitting approve for them to core developers is just a
waste...
Maybe you should add some group similar to previous (SVN) "commit
access to extensions", so a wider group of people could merge changes to
the extensions?