Demeter is inherently weak right now, but Hestia’s tech that gives +10 population for every 2 farms built around a towcenter is the most powerful and toxic tech in the game (especially in long games), and it’s only a heroic-age technology, not even a mythic-age one.
This is just a minor nitpick because I like its concept and I can easily see this thing being fixed and nerfed in the long run.
For example, it could grant +1 population instead of +5 per farm, forcing players to spend five times the resources to reach the population cap with this tech. That would result in more farms being built around a Town Center, which is also much more thematic and balanced.