openpgplint: encouraging best practices for OpenPGP keys today

Hi OpenPGP folks--

Between the recent SHA-1 development, MD5 attacks against other PKI
infrastructure, advances in computing power, and various nuances of the
protocol, it has occurred to me that most users of OpenPGP could
probably use some help in determining ways to increase the security of
their keys.

Following the model of lint [0], it occurred to me that it might be nice
to have a tool that scans an openpgp key and suggests changes or options
that the keyholder might want to consider.  I'm calling this (entirely
hypothetical) tool "openpgplint" at the moment.

I'm aware one size does not fit all, and different situations warrant
different configurations.  But maybe there's a way to present a
comprehensible range of situations, and then offer a series of
realizable best-practices recommendations to users based on their choice
of situation.

So i'm hoping to create a list of (a) typical situations where openpgp
keys are used, and (b) best practices for keyholders in those
situations.  If i can assemble something that looks reasonably useful,
i'd be willing to write some code to implement the checks.  Some checks
might require network access -- i assume that those checks could be
easily disabled by any automated tool, if a user wants privacy.
Suggestions and criticism are both welcome!

Here's a proposal for defining a well-secured, OpenPGP key that seems
reasonable for use by an individual communicating with other people with
modern OpenPGP clients over the next 3 years, as i understand the