Strategic resources are primarily used for constructing weapons and armor for your ships. Although this is a reasonable purpose, it is integral to the design of strategy games that decisions have tension between multiple options. To that end, I propose creating a number of compelling economic options for creating sinks for strategic resources. 


Access to strategic resources should be much more limiting, creating tense competition over those resources, and an active marketplace for buying and selling them.  



Advanced Resourcing Structures


First of all, structures of types which directly produce resources should generally cost strategics to build, other than the basic, lowest-tier version, which would cost only production. 


For example, it should not cost resources to acquire titanium from a planet which has titanium, or to construct a low-tier FIDSI structure. However, advanced structures which are unlocked from higher tech levels should cost strategic resources. For example, Miners' Union might cost titanium to construct, with each one increasing the yield of strategic resources by +1. A tier 1 food structure might cost no strategics, with a tier 2 food structure costing titanium or hyperium to construct, with more advanced structures requiring larger quantities or more advanced resources. 


Nearly every structure in the game can be created using only production, which means there is a clear optimization to focus production first, and then build everything else very quickly. However, this calculus becomes significantly more complicated when every structure costs strategics. It remains optimal only if resources are more than sufficient to build everything. If a player is unable to build every building everywhere due to limited availability of strategic resources, some care must be taken about which structures are actually needed, and how much production to build will depend on how many structures are going to be placed there. There is no sense spending massive amounts of resources on production structures, only to build only a handful more buildings and stop. 


It is noteworthy that there currently are structures which cost strategic resources to construct. However, there are not very many of them, and they are quite inexpensive. The structures which presently cost strategic resources should have their resource costs increased significantly. For example, the Microwave Coils only cost 2 adamantian and 2 antimatter. 



Upgraded Planet Specializations


Basic planet specializations cost only production to build. Higher level planet specializations will have larger effects, but will cost strategic resources to construct. Level 2 planet specializations will generally cost titanium or hyperium to construct. Level 3 will generally cost adamantian/antimatter. And level 4 will generally cost orichalcix/quadrinix. 


Planet specializations do not need to be individually researched; the entire tree of specializations is available as soon as the first one in the tree is researched. 


Superior planet specializations with the same purpose, such as a higher-tier Industry planet specialization, will cost the same amount of strategic resources to construct, and will be automatically converted when the research is finished. 



Specialized Resource Mining


Strategic resources naturally lead themselves to forcing players to trade with one another, such as a situation where one player has a large quantity of one resource, and lacks another, where another player is in the opposite position. To encourage this situation, improvements which increase mining yields should enable a player to obtain more quantity of a resource than they can use, but encourage specialization to do so. 


A simple (albeit hamfisted) way to do this is to have exclusive techs to build upgraded mines that only work for one strategic resource each.  So, the player is forced to choose; titanium or hyperium? The upgraded mines might be four times more effective (or more) for that resource only, and cost the next strategic resource to construct (i.e. adamantian needed to construct upgraded titanium mine). 



Reworked Strategic Resource Tech Tree


Titanium and Hyperium are tier 1 techs. Mines are free, and automatic. Used to purchase T2 and T3 resourcing structures. 


Adamantian and Antimatter mineable at tier 3 (down from T4). Mines must be constructed, and cost titanium/hyperium to build. Generally used to purchase T4 and T5 resourcing structures. These resources are used to build upgraded T3 mines for titanium and hyperium, unlocked using other industrial-related techs. 


Orichalcix and Quadrinix mineable at T5, no upgraded mines. These strategics are used to buy upgraded T5 mines for adamantian and antimatter, as well as some very powerful economic structures. 


Strategic mining improvements should also be reworked. Miners' Union also made T1 and also unlocked by one of the two T1 techs (need these resources to construct it). Miners' Union increases mine output by +100%, and is the cheapest, costing 10 titanium and 10 hyperium. Ordinarily Miners' Union will double one mine from +1 to +2, the same as presently. However, an upgraded mine that yields +4 instead of +1 will instead be augmented to +8. 


Adding even more strategic resource output facilities can push a single system's strategic resource yield to great heights, but each will cost a significant amount of strategic resources to build. 



Unique Improvements/Wonders


Wonders should require large quantities of strategics to construct, far more than for an ordinary structure. The resources needed to construct the project should be the main cost, and the opportunity cost of not using those resources in some other manner. 


Wonders should also use more advanced resource types than typical for their tech level, such as a T2/3 wonder requiring a large stockpile of adamantian and antimatter, and/or a small quantity of orichalcix/quadrinix to construct. Before the techs for mining these resources come online, they will be extremely difficult to obtain, generally requiring exploring anomalies and purchasing them in the marketplace from other empires who sold whatever small quantities they found.


A wonder race would consist of two stages; buying up as many resources as possible in competition with other players competing for those same resources to build a wonder. And then the race to actually construct the wonder after the resources have been obtained.