I have noticed some problems with how Debian is using the popularity-contest data.
popcon units are unknown
Using the popcon score of a package to measure its use is like using the bleeple score of a trip to measure its distance. Both scores have no sensible units attached, though they may be loosely derived from a unit value. Is a trip with a bleeple score of 99 a long trip? Is a package with a popcon score of 99 a rarely used package?
The only way to resolve this ambiguity at all is to compare ratios of values, so the problimatic units cancel out. A flight from NYC to AMS with a bleepie score of 99 is 50 times as bleepie as my drive home, which scores 2.
So, any statement like "low popcon score" is basically so lacking in context as to be meaningless. Such statements are deprecated, and should be ignored.
not all popcon scores are comparable
The above example is intentionally bad. Plane flights and car trips are not very comparable when you don't know what units (time / CO2 / distance / number of people sharing a confined space / security theater points) are being used.
Similarly, comparing a high popcon package like gnome-terminal with a relatively low popcon package like udhcpc is very deceptive. The former is installed by default in the desktop task, but plenty of desktop users would not miss it. The latter is installed only on embedded systems, which can exist in absurd numbers, and none of which will tend to report to popcon.
So, any attempt to compare popcon scores should include a rationalle about why the two scores are comparable. For example, gnome-terminal and rxvt are somewhat comparable since they are both terminal emulators. But, only the vote scores, not the inst scores should be compared, since gnome-terminal is installed by default. dhcp3-client and udhcpc are not comparable despite being similar packages.
popcon scores do not measure long tail effects
A strength of Debian is that not only commonly used, but also uncommon and niche software is packaged. Popcon does not measure the benefit of some little used peice of software being there, packaged and ready to use when a user needs it.
For six years I kept satutils in Debian, despite it probably having no users. It has a very specific use case, to control a motorized internet satellite dish typically installed on an RV. I did that because it was essentially no work (the package was approximatly bug free, and required no changes since 2007), and because of the possible payoff if someone needed this thing and there it was, in Debian. The value of Debian in that occasion would spike to a value that, while not directly comparable with a popcon score, would be pretty epic, for that one user, as they pushed arrow keys to move a satellite dish around.
(It also had the best WITHOUT WARRANTY statement I've had the pleasure to write: "If you break your dish off your vechicle using this software, you get to keep both pieces.")
Every removal of a package for "low popcon score" runs the risk of silently degrading this overall value of Debian.
who wants to be popular?
Part of the problem is that popcon has been around long enough that the connotations of its name, "popularity contest" have been dulled by repetition (and abbreviation). Popularity contests are not pleasant things. They rarely reach the best result. They embody the tyranny of the majority. The name was originally, to the best of my knowledge, chosen exactly to imply all these failings, to say that hey, popularity-contest is deeply flawed, but is better than nothing for this one specific use case (ordering packages to place on CD sets). We no longer think of popcon with these caveats. That is a regression in your brain. Fix it.
By removing packages that appear unpopular, we run the risk of Debian becoming bland and homogenous.