logan0178 & Larsenex, as parrottmath said in this last post and as I've said elsewhere, the timing isn't all that different between GCII and GCIII.
In GCII, playing casually as Drengin, I was able to have planetary invasion by turn 16--and I bet it can be researched faster than that. And as parrottmath said, blockading in GCII can be done within the first 10 turns.
In GCIII, on the other hand, the Drengin can blockade you in as few as 3 turns, but if they take 5 turns, you can already have a military ship built and stationed at your starport to protect it. That would mean you'd have to research military right away, and that changes the flavor of the game--which is a concern of mine.
But parrottmath brings up a very cogent point:
. . . the issue is not the fact that starports are too easy to destroy. Give the starport 1000 attack for each of their beams, kinetic, missles with 1000 defense. I would still win the game within 3 turn (unless their starport can attack) because I would be able to destroy every ship that comes out of that starport. Because I could have 15 ships surrounding it by turn 15. Each turn there after I could let myself build up what I will to win the game. It is not the fact that the starport is too easy to destroy, it is the fact that Drengin start with weapons and can start too close to the enemy to dominate them militarily.
End of parrottmath's quote
I disagree slightly with the idea that the Drengin having weapons to start with is the main problem--I think the real issue is proximity. As parrottmath said, "they can start too close to the enemy."
My suggestion for the devs is to work on the starting placement algorithm and to possibly limit (very slightly) the range of military ships (by increasing the size of the initial weapon components and/or the initial life support components). This means that everyone who wants to pursue a rush will have to research something first, slowing the rush down and giving opponents the opportunity to expand out of reach and/or build defenses.
I would like to see prototype weapons at the start of the game for each race. Weapons that have horrible accuracy, can overheat, overload and not fire. The research is to make these weapons more stable and consistent. Then the Drengin starting with effective weaponry doesn't make them dominate as easily in the rush game as they would have to counter act these prototype weapons. Sure they can do so, but I can now defend myself from that onslaught. When I see it coming then I can research the weaponry to defend myself better and match the Drengin. It would also make other players wary about invading to doing the cheap tactic of destroying the starport early game.
Another option since we don't know how tactical battles will take place, we could force defending scout ships (tiny or small ships only or possibly larger ships) the defensive option of Kamikaze. Giving them the ability to destroy attacking ships at the loss of them. The defense against this tactic is kinetic and they do as much damage as their HP or half their HP. But only as an option at the beginning of defensive combat, so you can either choose to use this tactic at the beginning or not at all.
End of parrottmath's quote
I think these are also interesting and viable options.
And not to derail this thread, but not knowing how diplomacy will work, I wonder if there is a diplomatic solution to the issue of starport vulnerability. For example, in GCII, I don't think you could declare war until after you had universal translator researched (somebody correct me if I'm wrong). Perhaps diplomacy and/or ideology will have some effect on declaring war, which in turn would have an effect on rushing...