Well, I think the best comparison for the Altarians is the Iconians.
Compare the molecular fabricator with the social matrix. The fabricator is better in literally every way:
- It appears earlier in the tech tree.
- It gives a 10% bonus to tech and manu like the social matrix, but the fabricator also gives 10% food.
- The fabricator gives +2 adjacency to manu, tech and food. The social matrix gives +1 to manu and tech.
Then the follow up tech is also better - +25% vs a 2x +5%
And finally, the upgrade of the fabricator (industrial fabricator) is better than the dark energy lab - by even more! Why? Because it gives +3 adjacency, where dark energy lab is stuck on +1.
The iconians precursor line in the eng tree is amazing. The altarians have no equivalent.
The iconians have good terraforming. The altarians are crippled by lack of ultra-terraformer
They have the dream conclave which is a truly awesome building
They get more morale starbase upgrades
So for all those reasons - and more - the Iconian tree is just a LOT better than the Altarian one