Finally a Solution for Base Attack Problem

[Lemon]

Well they do a crap job of advertising them and recruiting indies to them

Probably because indies aren't exactly trustworthy? Indies aren't exactly affiliated and could end up doing something stupid like I dunno, trying to leak sensitive information to the other guys? Something that already happens with people that are in official factions, mind. You let indies in by the dozen and make it public then you invalidate the entire purpose of having a war room if the enemy can sit in and listen to you organize.

Well, then you're screwed
I agree OP eg Enclave took a fleet to Cambridge and only defence was baf. Who lost a fight and then the Base was shot for an hour unopposed
In RP this is just moronic - entire Sirius would swarm another invading deep in house space

You can have secrecy
Or 50-60+ general defenders vs 6-15 attackers including people that aren't your buddies, but that will let attackers metagame join too. I vote for the latter