I've played about 80 hours of the game so far; one thing that feels off to me has been nation investment in miltech and some other maybe-related details on how nation investment works. The basic problem is that miltech requires massive, massive investment by a nation in order to meaningfully increase, on the order of years of doing almost nothing but military investment to make meaningful gains, even for massive GDP nations. This kind of "feels" wrong to me, since military sophistication at least in the context of Terra Invicta seems to be mostly based on the technological side (after all, global techs are what increase the cap).
The individual status of the nation's miltech at the open also ends up being very significant. The US starts at 4.7 and smaller, weaker nations start as low as 3.0, which is a gap that's functionally impossible to close. Small nations military is essentially pointless, and while I think on some level that's "the point" it feels bad that those nations won't ever be even slightly competitive or have any role to even possibly play in fighting off alien ground units. The level of sophistication of humanity's space forces goes up astronomically over the course of ~10 years in this game, but the ground forces probably won't. The AI as well, even when it plays a strong ground war game, doesn't optimize for military development nearly enough to end up being competitive with a min-maxing player, and military tech level matters quite a lot for ground war outcome.
Bit of a tangent, but another very weird behavior is how miltech level merges when nations unify. A good example of this that I played was when I had the US at 6.1 and merged it with Canada (which was somewhere in the 4s). Canada had 0 armies and the US had 6, and yet upon merging the two nations suddenly the US's 6 invasion era armies all instantly fell to mid-robotics era. I think that pretty clearly doesn't make much sense...
I think it might be better to change the military nation-investment part into something like "military effectiveness" which would be some kind of multiplier for how the forces perform and have a threshold based on other nation stats like the knowledge/corruption/GDP per capita and number of armies they're fielding. Then have a separate military tech score that's just based on a combination of global techs with "threshold" investments the same way as build army/nuke/orbital defense that only need to be cleared once to increase the nation's "military era". In my mind that ends up both making more sense and would probably feel better to play!
That's my thoughts for now, I'll probably have more feedback as I keep playing, thanks for reading.
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