Could I ask a more elementary question about corporations?
What are offices supposed to be? I mean, what would be their real world counterpart? Iam pretty sure your answer will be: "offices", cause their called that, but the way they are generating profits isn't like an office in the real world would do.
Offices which are founded by the corporation are founded to organize, distribute and advertise the corporation. They cost maintenance, but they are necessary to run the corporation. So the change Gazebo recently made (Offices increaes franchise limit) would be a correct response to the real world. But its really unlikely such offices would generate directly profit/yields, but instead increase the capacity to maintain a greater corporation and with it, yields to the corporation headquarter.
I mean, imagine an office, which is responsible for two franchises in a foreign country. Lets say the profit of those franchises is directed towards the office and not directly to the headquarter, founding another office wouldnt generate the same amount of profit as the first office would generate. The profit/benefits would be split to two offices, but not duplicated. Cause, why should the franchise be able to sell now double the amount of goods/services as before (or lets say, its really unlikely).
And the resulting profit to the offices are also questionable. Franchises didnt deliver anything towards their offices/headquarter, except paymant to use the name/buildings/products. Always payment, in Civ yields, gold. Look at McDonalds. Their franchises sell food and it make sense, such a corporation increase the food generation in the delivering cities (in this case, offices work like a agricultural network or manufactories). But in the same time, the greatest part of this additional food is removed, cause it is sold to the franchises. So, it make no real sense offices increase the food generation in the own cities to such a great amount while the franchise, which should gain the greatest part of the food, only get small numbers.
Its also questionable, which form of franchise would generate science in the home corporation. In most cases, laboratories, universities and offices for engineering are a great source of science, but its hard to imagine, which form of franchise would be such a thing in real world.
I know, not everything has to be represented 100% real world like in the game, but the way how corporation works in the game, is so distorted to me, that it was keeping me occupied the whole day.
And I think, it wouldnt be that difficult to create a relativly close representation of corporations and franchises in the game, that it could be maybe changed into that direction, if the results of the current change werent satisfying.
The headquarter wonder would give its general advantages to the player, like it is now, and the city which constructed the wonder, is the center of the franchise benefits.
Offices would would be cheaper to maintain and give small advantages, like +10% production/science/food/...... and strong extra yields on corporation linked luxuries, but mainly increase the amount of maximum franchises by, lets say 3.
Foreign cities with a franchise get a flat amount and/or a small modifier of the linked yield (like +2

and +2%

)
Every franchise in a foreign city grants greater benefits in the corporation headquarter city (+4

and +3%
OR +3

and +3% longer GA
OR +4

and +5% unit production
OR +4

and +1

for every 15 franchises OR ...)
The spreading mechanic could stay as it will be after the next patch, but with maybe 10% base spreading chance to random foreign city.
These are only my thoughts about a comparison of corporations in real world and in game, and how it could be made more realistic, without changing too much (The mentioned mechanics are already in use in the corporations). Small corporations are still competitive against corporations of wide empires, but wide empires have a much greater growing potential in the end