Whatever it is for Sid's Sushi currently, it should be between 1/3 and 1/2 that, in my opinion. In other words, the amount of food granted by Sid's Sushi currently is too high, assuming the current type of benefit formula.
Presumably there should be the same type of scaling for map size as currently for number of courthouses you need in order to build the Forbidden Palace.
A more fundamental issue, is that currently, the total impact of a corporation goes up as approximately proportionally with N^2, where N is the number of cities in an empire. Bigger empires have more resources (as well as can trade for more resources) on the one hand, and can put the corporation in more of its own cities on the other hand.
I think the benefit formula should be changed if possible.
Let R be the number of a given resource you have and let N be the number of your cities with a corporation that uses that resource.
Just as an example, the benefit in each city could be
proportional to:
Max[3, 1 + 2R/N].
So if for example you have 2 corn and 2 cities with corporations that use corn, then the benefit in each of those 2 cities is proportional to 3.
If instead you have 2 corn and 5 cities with corporations that use corn, then the benefit in each of those cities is proportional to 1.8.
If you have 2 corn and 10 cities with corporations that use corn, then the benefit in each of those cities is proportional to 1.4.
If you have 5 corn and 10 cities with corporations that use corn, then the benefit in each of those cities is proportional to 2.
If you have 10 corn and 10 cities with corporations that use corn, then the benefit in each of those cities is proportional to 3.
Under this formula, or some similar formula, larger empires which have more of a given resource and also can have the corporation in more cities, will get approximately the same benefit per city as do smaller empires. Also the benefit per city has a hard cap, regardless of how many of a resource you have.
Under the current system, larger empires which have more of a given resource and also can also have the corporation in more cities, get approximately a proportional higher benefit per city than do smaller empires.
I'm interested in everyone's thoughts on 'yield per resource' numbers for corporations, particularly how they scale with mapsize. I have something in place but I'm curious to see what your expectations are without me biasing it. Remember that cities can now have 3-4 corporations in them - in most cases up to 1 food corp, 1 production corp, and 2 commerce corps.
How many resources do you feel it should take to grant 1 yield on a Standard map? A Huge map? Or whichever size you play most?