There are some statistics that are mined out of Apache logs files for the wikidata dumps, but we don't really have any for the xmldumps. It would be nice to see if we can leverage the work that @Addshore did for wikidata to get some tracking for other dump files.
I would be interested to see number of downloads per month broken down like this:
How many folks are crawling most of the tree for a specific dump (i.e. revision content for all wikis)?
How many are downloading just one language or just one wiki exclusively?
What type of dump is the least popular (which tables, or which content-based dumps)?
Which small wikis are the most downloaded?
These aren't burning needs but they would be nice to have.
Wikidata team is processing them: https://grafana.wikimedia.org/dashboard/db/wikidata-dump-downloads?refresh=5m&orgId=1