But again, higher population in FM/Merc than in SP. Population = points, more GPP. That needs to be included in the balance.
SP also means: devoting time to constructing workshops instead of farms or cottages (or ripping up farms and replacing them with cottages when you switch.)
But corporations also means constructing the courthouses and losing a GP to do so. And SP also has the advantage of being conceptually 'easier'. There are a lot of factors to contemplate in making a corporation work properly. With SP, you know what you're going to get, and don't have to devote as much time to thinking through the strategy. A simple plan is probably superior to a complex plan because of the likelihood of it being implemented correctly and efficiently. At least, that's my gut reaction to all of this -- it's hard to quantify all the variables that go into a Civ game, of course.
I guess bottom line is that corporations are "viable" under the current rules -- in the right circumstances, assuming that you've laid the groundwork for it, and assuming you don't go crazy spreading it in your own cities, and assuming that no one else starts spamming your cities with corporations, and assuming you can spread it around in some friendly foreign civs/vassals (assuming they're not running and/or switch over to SP or Merc,) and assuming that whatever resource is provided is one that you definitely want/need to have in the quantities that it is provided. The problem is (to echo someone -- I think it was mrt,) I was expecting corporations to be desirable, generally, much like religion is. All the conditions applied to desirability of corporations...well, just aren't fun. Even if I don't found a religion or intend to follow a religion-based strategy, I don't mind when religions are spread to my cities -- it can be helpful to do so, even though the religion's founder is also benefitting. I was hoping that corporations would similarly echo this mutually-beneficial relationship far more than they seem to. I was expecting corporations to be something everyone should ideally want a piece of and if you can't get to them, or if you wanted to pursue a more militaristic/domination-oriented strategy and not worry about such things, here's the SP/CS synergy to give you a fighting chance. Instead, we have corporations which you can break even on if you're willing to juggle things to be just right. It's almost like corporations were designed by people who were overly enamored of existing strategies concerning the use of SP, and so sacrificed the desirability of corporations so that they didn't have to change their preferred strategy.
If Firaxis does not alter the corporate model at least a little, I will definitely be interested in seeing what evolutionary changes the mod community can come up with.
this sums up everything in a nice little package. corporations work in certain circumstances but have no huge advantage over SP when these circumstances are present. SP works in almost any circumstance that corps do, plus the ones it doesnt.