Galactic Civilizations II will introduce the concept of food into its planets.
Now before you give your views on this, please bear in mind that we'll have months of play-testing and beta testing to make sure we get the mechanics down pat. Starbases and constructors in GalCiv 1 weren't added in until 3 months before release - the whole concept came from beta testers. So much may change.
Anyway...
A given planet may have 8 to 10 usable tiles. These tiles can be used for 1 of 5 things:
1) Factories that make building ships and such faster.
2) Infrastructure that improves how fast you can build new buildings.
3) Buildings that improve the amount of research a planet performs.
4) Residential areas for people to live.
5) Farms that produce food.
The population of a planet is going to by the maximum of either the amount of available food or the amount of residential space for them. Some buildings will also provide some residential space too (i.e. an industrial area may provide enough homes for 1 million colonists). But residential areas will provide the space for far more people.
So the population of a planet will be much more up to the player to control. In the first game, the player had very little control over it. Only when people became miserable from overcrowding did people stop breeding. Now, food and housing can effectively limit the population.
Now right now, the plan is to NOT allow the importation of food from other worlds. Even though we agree this could be justified, it's purely a complexity thing. As cool as it sounds on paper to put together supply lines and such (That could be disrupted in war) we're just concerned that it coudl bog down the game. So on the importation of food issue, we may look at that as a 2.x feature. No one has requested this but it seems like a natural thing to ask for since we thought of it too. 
Some tiles will be better suited for food and others better suited for factories. Rare tiles will have special items on them (artifacts, super-fertile land, ruins, rare minerals) but like I said, that'll be rare.
What you may get out of this is that while the planet system will have more depth than in the first one, it'll actually be a lot simpler too. In GalCiv 1, by the end of the game the player might have dozens and dozens of planets that they were just arbitrarily building "whatever" onthem without much thought.
In GalCiv 2, each planet will be unique but with 5 different things to buidl on them and them having a base # of useable tiles on them there won't be a lot of things to do with them. By late in the game, the planets will be pretty set up and you'll be concentrating on other things.
That said, the BASE # of useable tiles on a planet will be 8 to 10. But then there will be another 2 to 3 upgradeable tiles (tiles that can be made useable with soil enhancement) and another 1 to 2 tiles that can be made useable with terraforming.
What we're excited about is that players will be able to try out a lot of different strategies. You can have your industiral world, your research world, your banking world, etc. In galCiv 1, all the planets wree the same except how much they produced which was limited by the planet quality. That seems, in hindsight, to be kind of lame.
When I was making the Prelude to war campaign, it became apparent that by the end of the game you're just queuing every single thing into the build queue via the governors and letting the planets go which means that planet quality was the deciding factor in a given game. No sort of strategic intelligence needed.
Now, before someone asks, why only 8 to 10 useable tiles. The answer is - we don't want the planet management itself to become a overwhelming thing. The planet management should be something that you set up early in the game and that later in the game it's more about designing ships, getting that key technology, assembling fleets, getting your battle stations and cultural centers into play. No one wants to mess around with the planets later on in any great deal. Hence, the limitation.
However, once in awhile, there will still be that class 26 planet (26 useable tiles) which will be quite valuable of course. 