I am considering creating tech requirements for the 40k worlds or possibly an archaeological requirement.
In the first case there would be a series of technologies related to each world in an ascending order of difficulty and researching each tech would unlock the decision for the corresponding world.
The second method could be a bit more interesting and more in-line with the 40k universe. There would be hidden events or possibly triggers based on technology level that prompt the discovery of archaeological sites within the players empire that lead to the discovery of SDCs that unlock the decision for certain 40k worlds.
Implementing the tech option would be easy, that is code I am familiar with, I haven't touched anything with the archaeological sites yet so that would take longer to do right but it shouldn't be too complex. Let me know your thoughts.

good, excellent mod, is there any way to start these planets with one?

Pls. reduce criminals on Hive Worlds, since 3.0 criminals producing -10 trade,
my Hiveworlds now producing negative Tradevalue

I am pushing out a new update here in a few minutes, part of that removes criminal jobs from the planet modifier. I will take another look at the districts, I may need to reduce those as well.

thx

Could you
1) Add a bit more descriptions to the worlds
2) Add a decr to the decision to change the world type
3) Create a quick refence flow chart for the world options (ie Normal - small hive -medium hive/Industrial hive ect)

While I am familiar with the worlds due to the OG mod, i feel the above would help

if i may suggest, housing should scale with pop jobs. new hab blocks for ever expanding hives/ manufactorums

that way the planet can actually use its unique type features.