In a game, mod and server so driven by player interaction, I would argue that it's not necessary to massively promote the idea with perks when factions as a whole are the easiest way to bring people together regardless of material benefit. You still get them even with a nerf, and joining a faction is a zero-cost endeavour. It's not like you're making something back as a result.
If you want to use that argument, the bigger problem is advertising the possibility of joining factions at all, rather than what you get from it.