[Twan]

I think rituals or other ways to repopulate provinces should be considered, with effects proportionnal to growth scale to make it a good option, but limited to provinces under x population (to avoid to see these rituals chain used on the most populated provinces)

In example a nature ritual, "ritual of fertility" multiplying by 10 the effect of growth scale on the target province for the turn may be a good idea for this (and/or the same as global enchant, and/or, why not, an astral spell summoning population from a parallel plane, adding a number of pop proportionnal to magic and growth scales, or a "summer of love" fire global augmenting the effect of growth in hot seasons.

Even with this kind of rituals, repopulation would be far slower than killing people with a death dominion + tax at 200 and pillages, and cost a lot of gems.

Another possibility may be a demobilization order, making demobilized soldiers become normal citizen (but it would be a big advantage to order/productivity and luck dominions more than growth ones).