David,
Thanks for taking a look at this. I discussed this at length with Adam Kennedy last night at ny.pm. He said that the feature creep was a side effect of the problem which finding one's home directory now poses in the age of internationalization, Unicode, etc. It appears that when you can no longer assume that your locale and all your paths are in English, reliance on environmental variables is faulty and you have to resort to direct system calls to determine your home directory. That's what that Mac::Carbon/Mac::Glue stuff was doing. Adam said he had expended considerable cycles dealing with this problem on Win32 and that he was going to discuss how it could be handled better on Darwin with Pudge.
I don't pretend to understand the issues fully, and I encouraged Adam to post here. As a short-term fix, you might wish to include a listing in the CPAN-Reporter docs about the prereqs, the prereqs of the prereqs, and what a user might expect when installing via 'cpan'.
Thank you very much.
Jim Keenan