The problem was not the base idea. It was more the availability of resources. On a large map you could easily get every single resource sid-sushi co. had to offer and see an obscene increase in the local stats of the city and in your national income every time you spread it.
Neither of both. Getting every resource doesn´t benefit more than getting that much instances of a single one the corp. uses, as every additional resource gives the same yield. On the contrary, having every resource blocks the corp owner from the "Hostile Takeover" quest, which enhances the never "obscene" money income from it, if completed, at the expense of a war.
I've had games where the gold cost to spreading it was made back up in a couple turns from the gold gain even on 100% budget expenditures. Religions were a much more reasonable give bonuses to every city feature.
I play Marathon, so can´t know exactly of other speeds (but it cames up to be exactly proportional in all cases but some aspects concerning units cost&movement), but the expense of spreading -which I rather have it changed a little bit as I mentioned earlier- is never ever made back in a couple of turns. Something is wrong with that math; even in the optimal money back case where you only have one resource costing mantainance, +%200 gold in the Headquarters, you end up with more than 7 turns to cash in the investment. Regarding the expansion is in your own territory, you have already the Wall street in HQ, you are runing Free market. And you have to add the cost of the Corp executive.
Religions spread many times by themselves, are non erradicable -contrary to corps- and they also need a GP to cash in that churches income, as corps.
Claims over Corps being "obscene" or even umbalanced, just don´t sum up in the thorough analysis. The trade-offs the player has to endure to make them optimal (as it is the situation taken as the norm, even it is not) are immense. To name a few:
- Are constrained to Free market (even if you hace awful trade routes and will be better off with whatever other economic policy)
- You need a specific GP in the right moment (keeping for aeons the needed great person is quite suboptimal, and it doesn´t even secure the corp for you as it is a WW)
- Need the wall street as early as posible (expensive building needing a lot of banks which you many times can´t or just won´t rush if it weren´t for this strategy. Hence, big trade-off)
-Have to invest some money (should be more, according to the city size, etc) to expand it, and some not minor amount of production. More money to make it foreign.
- If you take it foreign you get nice gold (after 20 turns aprox regaining the investment) provided the foreign country doesn´t go into Mercantilism or State property (very common indeed). Plus you are giving the use of the corp to other civs. All this makes it a risky move.
I am surely missing something in the list. Anyways, I can understand people who are very used to play always the same style, the same empire model and structure, and possibly very loosely with the difficulty level, tend to see corps as being umbalaced. They can do with some minor tweek, I believe, as in the cost of a new expansion.
I have one mp game in which I actually had to get rid of all the imports and even get free of some corp. resources I had because I got involved in a difficult war and the costs were sinking me, not paying off at all (Sid Sushi´s mind you), and I needed the budget for upgrades, espionage, etc.