I've been reading and thinking a lot about Capital Ships vs Cruisers vs Frigates.
It is clear that Capital ships are a special part of the game experience and that it seems disproportionately easy to get a capital ship vs getting a cruiser in term of the research involved in unlocking the ability to build cruisers. In real terms, Capital Ships would represent a significant amount of resources for a civilization to build. So I started thinking, what if Capital ships were more one of a kind. What if you only got one of each type in any given game depending of whether you had meet a certain set of criteria to get a capital ship of that type. This would add a bit of depth to the research tree, and would provide an incentive to research higher into any given tree.
An example of what I mean. Let's say that you start a game with no Flag Ship. You start the game building 15 Cobalts and research the entire first level of combat tech. As a reward for reaching this milestone, you gain the ability to build one Kol for free. You can not however build any more Kols. Therefore that flagship becomes extra important and special. When you have succeeded in gathering enough resources to research the third tier of Combat and the 1st Tier of Colony you unlock the next Capital ship. Maybe you could tie unlocking a type of capital ship to controlling a planet of each type, or controlling a certain number of the same planet type. The possibilities are endless.
Another way to handle this might be to make capital ships more like wonders of the world in Civilization. Every society can build one of each type, but it takes a protracted effort to build.
It also might make sense to attach each time of capital ship to the cruiser type that matches the flagship type. Researching the carrier Cruiser means you can build one Carrier Cap.
Of course you could add a technology high on the combat tree that allows you to build all the Capital ships unfettered.
Just an idea. What do people think?