When you're gathered together with at least 3 other members of your Free Company, it would be nice if there were innate bonuses that are not FC actions, like a power up buff that increases power by 2-5%. Maybe only 2% when you're in a 4-man, with all 4 of you being FC mates, and up to 5% when it's an 8-man.
Currently, other than housing and FC actions, FCs are just another chat channel, and we have linkshells for that. I just don't feel like being in an FC is that big of a deal right now.