Oh my God! This is so much work! Space Engineer you have opened the Pandora's box!
No I mean in the good sense! I am only sorry for you because now the complexity of the program has increased exponentially..
Anyway this is great news! I only have one comment / suggestion to make regarding planet atmosphere generation:
Now some planets with high g's have very dense atmospheres at their surface level but, at higher altitudes, the atmosphere is getting very thin, very fast. What I mean is that you can practically stay in orbit around such worlds at ~15-20km altitude because the air pressure at this altitude is practically zero whereas on their surface it can be thousands if not hundreds of thousands of atms.
I can understand that the high gravity may be "compressing" (sorry can't find any appropriate scientific term for that) the air molecules towards the surface thereby increasing the pressure tremendously at the surface level and causing very high gradient reduction of pressure as altitude from surface increases. But still it feels absurd to be able to orbit such worlds at almost contact altitude.
Similarly at relatively lower g worlds the atmosphere may rise very high above the surface. So you may find worlds with 0.3 gs for example with atmospheric heights above 200 kms. And with surface atmosphere pressure not exceeding 0.01 atm.
So is this new chemical model taking into account this issue? or at least reduces the intensity of it?
Sorry for long post - I am just very excited for this release.