CPAN River - water quality metric

At the London Perl Workshop I gave a talk on the CPAN River, and how
development and release practices should mature as a dist moves up river.
This was prompted by the discussions we had at Berlin earlier this year.

Writing the talk prompted a bunch of ideas, one of which is having a “water
quality” metric, which gives some indication of whether a dist is a good one
to rely on (needs a better name). I’ve come up with a first definition, and
calculated the metric for the different stages of the river:

http://neilb.org/2015/12/22/cpan-river-water-quality.html

Any thoughts on what factors should be included in such a metric? I think it
should really include factors that it would be hard for anyone to argue with.
Currently the individual factors are:

Not having too many CPAN Testers fails
Having a META.json or META.yml file
Specifying the min perl version required for the dist