Most of us have played ALOT of shooter games. I myself have probably played and owned 50+. They are without a doubt my favorite genre. Most of us also realize ones that depend on a thriving online community burn brighter, but swiftly die. That's why they make a new battlefield or call of duty every other year or sooner, to keep it fresh. In the myriad of shooter games I have NEVER wanted to be in a guild or team. I like playing exactly as long as I want when it's convenient for me. Part of it is also because I am deaf and people get frustrated trying to play AND type out direction for me, and I also get frustrated with their impatience. This is the first game I have EVWR wanted to break that rule in 15 years. Well aside from age of reckoning. But that is a fantasy game. It's not that this is the best shooter game I have ever played. Far from it. It's that it's the only world I have ever CARED about in any game. And the players for the most part are in the same mindset. They certainly because they were 40k fans. I have a lot of anger issues, but I finally realized they stem from an overwhelming love of the IP, and my desire to see it succeed more than any other game I cared about. And many of the angry fans now are the same. Fanatic to the point of insanity, and no one can love or hate with more passion than the insane. I am here because I get to play a game with a niche group of players who genuinely love the setting even more than the game. And that is what we need. We need everyone to join guilds, alliances, the community. We are going to be the biggest pull the game has. People have to be attracted to playing with a group in it for the long haul because there is something about this mismash of 80's science fiction movies that we really love. I'm not here to play some lobby shooter. I'm here to run wild with my fellow ork fans shooting at anything we see, in between getting my fingers stuck together with glue after putting together another ork contraption. After all, the tabletop rules have been garbage for two editions now and I still play. Because when I show up there are 15+ people as obsessed as I am, waiting for a game, complaints about poor rules and all. Because it's what we love.
The first thing that makes people play a game is other people. The public warparties system need a revamp, it's too difficult to create a group from scratch.
You already said why it won't work: the reason why you like the community is because all of us are 40k fans. People who will come at launch have never heard of 40k before, so the community that is based around setting wouldn't work. Also, they make new Call of Duty or Battlefield games every year because they want money. Even when they shut it down, there were still people playing Battlefield 2.