If you can get a brilliant series of planets in a relatively small star cluster, that is the holy grail!
I have had good maps before, but typically always involving a larger area, so what happens is that my generous expansion is at the cost of the AI having less planets which is very bad...... and i have quit plenty of good starts for that very reason.
Its one thing having a single excellent small star cluster.
But that game, I expanded to three star clusters having 2-3 earths in almost every star system + expanded half of the fourth before I was stopped by AI colonization.
Dead planets is too useless in galciv3 currently, I only can hope they have some kind of purpose in further expansions other than being a possible planet spot for benevolent civilizations.After all, I'm pretty sure there is iron to mine on planet mars.. There's probably something to mine off Mercury + Venus if we can develop the machinery that laughs at heat + pressure and whatever.
Then there is gas + water on Jupiter and Saturn moons.Then recently confirmed that Pluto has ice on it. Europa + Enceladus has water + Ice.
Titan has gas. I only can wonder if I was to light a fire on titan, it would set off one hell of a fire or not. About Enceladus, if it has something like fishes, and they're edible to us.. And if any of the moons has metal for us to use. Then only issues left is the radioactivity + possible abrasive soil. If we can eliminate those issues then Saturn's moons could be a viable colonization target.
Back to Jupiter's moons.. Europa for obvious water. and possible fishes! Then metal might be mineable on Io, Ganymede, and Callisto. Again, same issues of abrasive soil + radioactivity.
It's clear that Gas Giant's moons will be harder to colonize due to radioactivity alone. But they have to be considered due to possible source of animals for us to hunt which can ease the burden of transporting goods. While Mars can't be considered like that. Saturn might be more preferable due to possible easy source of gas on Titan.
Because of all those factors, gas giants in other star systems should have closer look done on them because their moons could be a viable source of resources.
Even with all those possibilities, no one really wants to colonize a dead planet because it's a damn dead planet. So generally other than "FIRST!" there needs to be some kind of profit or gain motive to grab a dead planet and make it yours. Population on them would never likely be that big, a colony of miners + Scientists and maintenance Unless the general population of the future has a different mindset and is all cool with settling them.
Of course, all this is without mentioning the gravity problems.