I'm sure this is possible to mod, but I wouldn't know where to start. A lot of games have challenge modes which basically just test your ability at some small part of the game.
If there was a mode in FAF where you had to achieve a certain structure or number of units as fast as possible, it would encourage even the noobiest of noobs to improve their build orders, and it would help the likes of me (want to be good at the game but a bit too stupid) improve as well.
I'd envision such challenges as things like:
* Limited to four mex points, build 50 T1 tanks
* In Seton's back slot, make 5 ASF and 1 strat bomber
* Using only reclaim, make a Monkeylord (Daroza's basically )
* Using only four mexes, make a cruiser, a destroyer, a shield boat and a battleship
Although you can of course muck around in Sandbox to your heart's content to figure out the best way to do these, if there was a competitive angle and therefore discussion about them, it would help more players improve more quickly.
Thoughts?