[X][Food Production] Green Belts
Said it before, said it again, it's just ridiculously good and synergizes with our entire society, especially since Verdant Worlds doesn't actually create Maiden Worlds. We need to think bigger guys -- this basically solves organic resource requirements for our entire society, asteroid belts are fucking enormous. This means we can supply our Pilgrim Fleets and their efforts better, it means we can feed Van Zandt if their resource worlds get crunched, etc. It's stupid good, and IMO Verdant Worlds isn't competitive with it when we're already getting Paradise Worlds with Sacred Sands.
[X][Heavy Industry] Roaring Engines
I'm fine with Grand Note, but this synchronizes very well with Green Belts but also just lets us hit way above our weight. Also, don't you guys want to see more Dreadnoughts?
[X][Medical Services] Untouched By The Coming Tide
We're already extremely resistant to Chaos, but being resistant to stuff like Ork Spores and Tyranids means that we're going to be very resistant to the two biggest other sticks in the setting.
[X][Military Industry] Canticles of the Machine-God
Fine with immune to morale penalties, but I like automata. That being said, I plan on taking autonomous so that's fine enough for me.
Ultimately, while I'm neutral on MilIndust, I think the first 3 are very synergistic. We can hit way above our weight because we can utilize all our space much better (something that leans in on Icon5) AND get just somehow Produce Three Times More military industry. One action produces 30 Flag Armadas or 300 SBGs. That's literally more than our current Fleet Cap for SBGs, it's absurd.
And being resistant to Chaos AND Orks AND Tyranids is just icing on the cake.