I realize these aren't yet available, but before they do get implemented, I'd like to make a suggestion:
DON'T HAVE THEM.
At least, not in the same sense that GC2 had extreme planets. That is, in GC2, all races colonized the same basic type, and "Extreme" was the same for all of them, the ability to colonize depending only on access to certain techs. And the Terraforming techs applied to ALL planet types.
Rather, I'd prefer that we took a more nuanced view.
- Categorize all planets into (maybe) 8 different types: Gaseous, Aquatic, Frozen, No Atmosphere, Heavy Gravity, High Radiation, Toxic, Normal
- In each category, there should be 5 "levels", corresponding to the 50% production, 100% production, then 3 Terraforming techs from GC2
- Each race should be assigned a "native" planet type. They automatically get the first 2 techs in that type.
- Certain races may have additional planet type techs (e.g. Iconians).
- Each race should have FORBIDDEN planet types - not only should they not be able to research that planet type tech, they shouldn't be allowed to trade for that tech. This makes is more interesting when there's planets out there that you simply can't ever use, but others might be able to. And also seems logical, because presuming all races can colonize any planet with just "the right tech" seems a major stretch.
- Terraforming is now planet-type specific, and must be research for each planet type. Do away with "generalized" terraforming.
- For planets which you don't have the minimal tech for:
- Invasions merely wipe out the current population, and change the ownership of the planet. The colony remains at 0 population, and all production/economy/etc is zero-d out.
- You can't influence-convert the planet
- Obviously, you can't colonize the planet (i.e. you can't put a colony there if none exists)
- The 50% penalty applies to ALL aspects of the planet: research, production, and economy. Unlike GC2, where it only affected production.
If I were being mean, I'd say there should be an initial 25%-level for each planet (i.e. three techs: 25/50/100%), and possibly block advancement in certain planet types for each race (i.e. not just an "all or nothing" ability to work a planet type, but limit advancement to say no more than the 100% tech - no terraforming - for certain planet types, or even the minimal 25% tech, etc.)
One other thing: vary the number of new tiles available much more randomly. High "initial quality" planets should have just as much chance of having many new tiles exposed by the new terraforming as do "low quality" planets, and the inverse. Additionally, make it so each terraforming tech doesn't always expose the same number of new tiles. This gives you a much more varied planet selection. In GC2, I often found that after researching all my terraforming, pretty much all my planets were PQ 12-14, regardless of how they started out. I'd much rather see a higher deviance, because, once again, planets simply aren't created equal, and no amount of tech will change that.
