Quoting WIllythemailboy, reply 33Frogboy has said that planetary output (research, production and money) are going to be directly related to population. Structures are going to be giving percent bonuses on top of that base rather than giving fixed output per building. I can foresee some really cheezy 30+ billion planets cranking out ships absurdly fast if they remove the primary control factor on an individual planet's population.
That may not necessarily be the case. If the base output of the population is relatively small, then you need the percentage bonuses from the improvements in order to increase it. Therefore, you won't have the space to build lots of farms.
Take a look at the PlanetScreen-alpha01.png from the vault, for example. Earth has a population of 24.5 (of 30), two Advanced Factories, and one (two?) Research Centers (one is definitely still being build), yet the values for Manufacturing, Research, and Wealth, are only 13, 8, and 3 respectively. I don't know what settings for the spending are used, but those values seem pretty low to me, considering the population.
Besides this, there are other ways to limit the population too. For example, the PQ and the type of planet you colonise.
Still, I'm really curious about what the devs have in mind.
In GC2 terms, it only took 1 advanced farm on a +300% tile bonus to get to 32 billion population. If you were willing to do it, the Thalans could get 40 billion by dropping the matrix on one of those tiles - and if you did it on a class 25+ planet, it would leave a lot of room for factories and such. Clearly population isn't going to work quite the same this time around since Earth is at 30 with no farms at all, but ramping up to really large populations can be done very easily on certain planets.
Take a look at the level of bonus provided by those labs. With such a small base, those increases will be trivial. There's something else going on here mechanically, and we don't know enough to speculate properly yet.
Since this is getting pretty heavily into founder's information, we should probably move this discussion there. Or just wait a couple weeks, but what's the fun in that?