Some of the ideas floated in this thread are great.
The ability to customise aspects of the hostile worlds when creating your game is definitely high on the list of things I'd like to see...How many are they? Are the randomly placed or in fairly tight clusters (would make for some interesting tactical scenarios if entire solar systems were made up of hostile environment planets that could not initially be colonised in the inevitable 'rush'...
Spacing the hostile environment techs out amongst the tech tree is also a good idea...It would also help make it harder for civs to easily research them all rapidly...
Having bonuses for the planets is defiantly something I'd like to see...You've expended a lot of effort to be able to get to those planets...There should definably be a big juicy carrot dangling their enticing you to grab it before anyone else does...Nothing silly, but as has been noted, the natural environments of these planets would lead to all sorts of exploitable traits in theory...
Personally I dislike the idea of Gas Giants being colonised...For one, it would create to many colonisable worlds...There's gotta be SOME empty ones guys...And secondly, the gravitational forces, wind speeds etc make it almost completely un-viable from a realism point of view. I know, I know, it's scifi...But you've gotta draw a line somewhere...Maybe they can be used for some other purpose, (in the Saga of the Seven Suns books they were used to get fuel for starships...) but I'm not liking the idea of making them habitable...
It would be great to see the devs take a look at this...
Keep up the great work guys.