I'm just eating popcorn at this point.
Cosmical, to answer your question. Yes. It is possible to blend the hardcore and community aspects in a successful outfit. Being able to be both is simply not buying into the mentality that you always have to do things one way. In TFS-J our voice comms could go from story time to dead serious gameplay at the drop of a hat because it reflected the state the fight. Having people who actually enjoy each other's company and a have friendly attitude to new members breeds camaraderie. The building of traditions and jokes over time also helps cement the community in and outside of the game.
The problem that I've found is that building a good community is easy but keeping it together is hard. People care about what they like and people don't agree on a lot of things. So conflict is constantly brewing somewhere in the group and the ability to deal with it is what decides if the clan sticks around.
There are also long term and short term threats to the group probably the biggest of which is finding replacements for the leadership when they get tired of dealing with the continual stresses but still want to play. Also the leader not being stupid enough to think that he/she always has the best solution or indeed a solution at all helps.