I tried looking for information on how the Marian reforms trigger, but could not find a definitive answer on the latest versions (2.3 / 2.35). Is it so that the highest levels of agricultural development in all of Italy plus a suitable leader is needed, and if those conditions are not met, it happens anyway when it did historically?
My motivation for asking is that I am trying to play my game without upgrading agriculture past a certain level, and I am concerned if the reforms then take place at all. The reason for doing so is that I try to see how far I can do without the negative consequences of slave-operated plantations. Perhaps the in-game penalty is not so high anyway, but I am trying to imagine an alternative history in which some form of Roman peasantry remained.
For further discussion, so far (~200 BC) it seems that managing starvation can be done without upgrading farms much. Also, population growth seems to be very manageable that way. Run-off population growth was one of the main problems I had with Rome: Total War (nearly broke the game for me), and I have been trying to avoid it as much as possible. Probably at the expense of my finances in the current campaign, in which I am often unable to achieve things because of lacking funds. Then again, most of my settlements are happy and the family members are generally getting good traits.