I personally can't find good changelog for nightlies. One you linked is better than nothing, but it's not that useful too. It says no changes in last 2 nightlies - how can it be possible? Why release them then?
It seems that there are no changes to nightlies from change log. Cm 7.2 is old and stable for most of the supported devices. Focus of cyanogenmod has already shifted to cm9->cm10->cm10.1 so it makes sense. These nightlies are compiled by bots so there is no human involvement(and that is why there are new biulds) . So unless someone makes cm7.2 or device specific changes to code nightlies will remain same.