I'm late to the party here, but I have read the the whole thread (mostly). On the subject of player retention and advertising what FAF really is at ground level (as opposed to the surface, i.e. shiny robots & explosions), my suggestions are as follows;
First, pick a few RTS Streamers and invite (pay) them to host a mini-series in which they learn the game's mechanics alongside veteran players. This would allow said players to briefly explain how FAF has significantly more important economy considerations than other titles, on top of the normal unit microing and tech factors of actual battle, and why that makes it a more satisfying experience for the armchair general.
Second, the current streaming community, while dedicated, is both small and geared towards existing players/fans. I suggest that on both Twitch and Youtube, we create an official FAF Streaming channel in which groups of players can casually talk about how the game works while playing at the same time, effectively explaining as you go. We could also have Clan involvement here in order to expand community interaction among our own playerbase.
That's all I've got for now.