maybe something you can use for balancing:
I was further trying out the Norlamnin and found the issue I had with them was because I tried to play them different to both the Cators and the Trade Alliance. But in fact the trade is key if you do the math (heavily simplified):
After startup if you get ~3 additional planet/asteroids you will get a base income of about 10 credits, 5 iron and 5 crystal
If I got it correct: doing all cost reduction research will give you 30% on everything, requiring 9 research items.
The mining bonuses are the worst way to go because of many research steps and the lose at cross-selling. So if I have much iron, you get only 50% value by selling. If you need to buy crystal then the value is again reduce to ~25%. So a 10% bonus on iron will leave you worst case with ~1% real value. And researching bonus for our low crystal mining will give you according little increase. A 10% trade bonus instead will even worst case (buying iron or crystal) give you 25% value.
With one research item I can get Trade ports, with four (one port at each planet) giving ~5 credits. The big advantage the trade ports also have is speed: After the research I can build them as fast as I get money to get even more money and I get additional bonus by trade treaties and any new planet will increase the production of the others when increasing the trade route length.
This I think is the reason the Trade Alliance is so strong at start. Trade ports are the fastest, most effective and efficient way to increase income. The Trade Alliance weakness is their culture. When planet become unhappy the income drops.
The Norlamin culture advantage gives them a bonus, but which again limits playing flexiblity. For a competitive play you research trade, research and culture. This takes so much time, when I get to mining or cost reduction it is already close to finish.
I would like to have the Norlamin more original: What about reducing their trade and increase the cost reduction bonus? Not sure about the mining, I would leave the big mining to the cators. The Norlamin mining could stay as it is for the case they get an mineral planet early on.