This was a feature that was added into expansions of GalCiv II if I remember correctly. There were certain techs and racial abilities that made certain planets habitable. I think that keeping the number of habitable planets low is important to the feel of the game, but advanced techs that make a few more planets habitable would be cool.

KHAAAAAAAAAAAAAAAAAAAAN!

(Sorry...I couldn't resist.)

I wouldn't mind seeing the ability to send a terraformer ship to one of these planets (Shake and Bake Colony) with a percentage chance of success. Something around 5% chance of successfully terraforming a dead planet. Building these terraformers shouldn't be cheap and you would fill these things up with colonists .5 billion, with the planned effect of them possibly dying on the planet. Brings a little gamble in the game. Once terraformed you can transport colonists to this newly created world.

The terraforming should take time, and the terraforming while being done is a economic burden.

Do it.

I dare you

Like many others I really like the idea of terraforming and it should be slow and/or expensive. This thread has dealt mainly with dead planets - what about opening up more tiles on habitable planets? You settle a planet and have the area around your outpost cleared, and you gradually open up more sectors to build in. Then planet size will matter far more. A large habitable planet on which you can open up the full planetary map for exploitation (after a lengthy investment) would be hugely valuable. And it's planets like that which provide a focus for war and combat. While it may add in a level of micromanagement or delay that some might not like, I think there would be plenty of turn based strategy players that would love the long game. Perhaps a special game mode for an expansion?

I don't want to derail your OP, and I agree with the "habitable zone" limitation, overall, but think it would also be interesting to make some planets, like gas giants, be able to support a colony plus a few tiles. Perhaps these would have to be specialized buildings specifically for gas giants--i.e. a cloud city for colony/capitol & airborne equivalents for manufacturing, research, economy, influence, etc.

This could also be adapted to planets that are too cold, too hot, have no atmosphere, etc. via biodomes and other artificial life support mechanisms. This isn't technically terraforming, but it relates to the use of "dead planets" and those that have a planet class of zero.

Again, I think more options for developing infrastructure is a good thing, but I'd rather the devs focus on the core game first. Terraforming and colonizing other unusable planets could be a DLC or a really cool feature of an expansion.

I don't remember that from the stream, but I had to get up a couple times, so I must've missed it. Thanks perigrine23.