Quoting Ben Hutchings <ben@decadent.org.uk>:
- Would it make sense to split the changelog, leaving older entries only in the source package?
As long as the full d/ch is in the source package, I'm fine. On one of my embedded machines changelogs are 2/3 of /usr/share/doc. E.g. multiple copies of the same changelog for the various binary packages build from bind9. The custom kernel package on my device doesn't install docs :~)