For one second, I was like "isn't the fertility boost with worm already there", then I realize that is the mod Primitive Survival
Talking about the "overpowered" farming, tbh, the farming being so powerful is why humans chose a relatively stable form of agriculture rather than hunting and gathering. And the current farming power is based on scale effect and without noticable natural disasters to harass the exponetial planting area. Other factors like irrigation and hydrology, pests and diseases, are hardly simulated in the game. And like you said, the game also has to consider the harsh beginning for the new player, and may not put detailed land reclamation process as an obstacle. These are real farming challenges that may not be easily implemented and even implemented, become interesting.