Formation Level Capabilities, rather than Element Level Capabilities
But why? And what would happen if a unit/element is moved from formation A to formation B? Will it lose formation A capabilities?
As it stands, to have various different formations with different capabilities you have to research several copies of the same element with the only change being their capability. If I want a formation that has jungle fighting, a formation that has mountain fighting, a formation that has desert fighting, and so on, I have to design and research what is essentially the same unit several times with the only difference between them being capability. God forbid the element I'm trying to give capabilities has various element types in it because that compounds the issue. At that point, the list of ground elements is going to be so cluttered with dozens of units whose only distinguishing factor is that one fights slightly better in extreme temperatures, one fights slightly better in the mountains, one fights slightly better in the desert, etc.
Any combat-related supporting elements will also require various versions, including artillery. So now you also have to research various different capabilities of artillery.
Then, if you have any HQs that double as combat units, you're going to have to research various different capabilities for them.
What I've resorted to doing is making "Elite" formations that have all capabilities because the micromanagement and clutter of 7 of the same-but-technically-different riflemen, tanks, artillery, etc., is just not worth it in my eyes. If one could just build, say, 6 of the same infantry battalions, then select the formation and do just a few clicks to give them a certain capability, then in my eyes it avoids a lot of player headache.
As for what happens to units moved from formation-with-capability to formation-without-capability, they would lose the capability, moral, and if the cost is greater you pay the difference (if not, you don't.) Again, I picture this as "retraining, rearming, refitting" whatever abstraction works for you. An alternative is that capabilities gets applied to the elements by the formation template. As in, I mark a template as having, say, desert warfare capabilities, its cost increases at the rate of the desert warfare capability, and once I build the formation, its elements have the capability.
I'm mostly just spitballing, I'm sure there are reasons like this that inevitably made Steve decide on capabilities being on an element-by-element basis rather than on a formation-basis.
Reduced Missile Radiation Research Line
We can research enhanced missile radiation if we want to glass planets, but what if we could research reduced missile radiation for tactical ballistic missiles for use in assisting ground forces without ruining the planet?
You can do that already via orbital bombardment from space ships and having FFD units on the ground. Having "clean" missiles that you can shoot safely from outside STO range means that they would basically lose their effectiveness completely. Currently players have to choose between bringing their ships into harm's way if they want to take the planet intact, or just glassing it into an irradiated hellhole.
Fair enough.