First, when temperature is good, green (forest) would appear on the planet. Just aesthetic, no real function./Yeah, I think this is planned to be implemented. But there a ton of other factors that have to be right if you want life.
Secondly, 100% Water Planets would be a giant bubble floating in space, and It would be destroyed by too huge heat, or turn completely frozen./ Actually, planets made from completely water would be so heavy that the pressure on the inside would turn to ice. It would be an actually planet. Also, even if this wasn't so, gravity and surface tension would be too strong at this point for it to be a bubble.
I also think an "atmosphere composition" would be good./Yeah, I mentioned this before as well. Who knows, we might see somehting like this in A-12!
Forestd would increase oxygen./ you never know. They are aliens, so they could convert any gas into any gas, so not just oxygen. Maybe just oxygen to start with, but more gas conversions later on.
And finally, atmosphere, forest and ocean color editor, to make custom and fun planets !/I suggested this a while ago, and Dan said that they would be implementing this soon. Chad also said in the livestream that we would be seeing this feature in the near future as well. I'm very exited!
Yup, pretty good ideas you got there