Hi,
the original mod is meant to be played on large unit size. Because I prefer huge, I edited the export_descr_unit and gave every government building a + 0.5% population growth bonus, so the settlements don't get depleted.
Just put the attached file into Rome/bi/ci/data. To see wheter or not you installed it correctly, start a campaign and open the building description of a governor building. If it says that the building gives a + 0.5% growth bonus, you did everythingh right.