I think in this case narrowing down the scope is the winning ticket. Hardcore fans aren't interested in discussing anything else. It distracts from fandom. I also think the sub communities should be tied to an umbrella community. For instance, if SPORTS token was the catch all for individual sports (basketball, baseball, tennis, etc.) and each of them had a token, as well as team communities below those sub categories you could synergize with their competitive nature and they'll pump each other. :)