I am a CPAN author (<full disclosure>with only 2 active modules certainly not a major contributor, but every little bit counts</fd>) and I do not have nor will ever have a Google account (that's not because I think Google is EEVIL but because I am careful about what information they get from me). Also, I work on a 64bit-Linux system, which by your own statement would prevent me from using this tool.
Aside from the fact that this system would exclude me, I find the all-including nature of Perl and CPAN one of their most appealing features. So I would strongly disagree with adding any tool into the general CPAN infrastructure that does not support a wide range of diverse clients. If you find anno-cpan lacking, maybe time would be better spent improving it?