Consider what sort of questions a Stack Exchange would gather if it were the Cthulhu Mythos Roleplaying Games Stack Exchange. There would be mechanical questions about Call and Trail alongside historical questions about how long it takes to get from London's passenger docks to the British Museum by taxi and when the telephone became ubiquitous in America.

The point is that all of those would be on-topic for that SE. And if such historical questions would be on-topic for an SE about Cthulhu mythos–based games, it follows that such questions are on-topic for a SE that is about all roleplaying games, including those Cthulhu mythos–based games.

So here's the heuristic I'm proposing:

• If a question is on-topic for a specific roleplaying game, it's on-topic for the Roleplaying Game Stack Exchange.

I know you're probably worried about questions getting bad answers because you're worried we're not expert enough in those sorts of questions. I suggest this isn't worth worrying about. For example, few people are expert enough in how Reign's Company rules work to give good answers, too. That doesn't make it off-topic—it just makes it special-interest. Rest assured that the people who are interested in a game will be expert in the things that are relevant to playing that game, whether it's the nuances of social life in Vichy France or the names of obscure pole-arms.

If the question is too hard to answer because it requires expertise we don't have, the system will take care of that for us. We don't need to police such questions. What will happen is that it will be low-voted, and hang around for months (or years). Then someone who is exactly the expert the OP was looking for will discover it, answer it brilliantly, and then the question will have served its purpose.

Essentially, stop worrying and learn to love the voting system. Give the system a chance to do what it does best.

Consider what sort of questions a Stack Exchange would gather if it were the Cthulhu Mythos Roleplaying Games Stack Exchange. There would be mechanical questions about Call and Trail alongside historical questions about how long it takes to get from London's passenger docks to the British Museum by taxi and when the telephone became ubiquitous in America.

The point is that all of those would be on-topic for that SE. And if such historical questions would be on-topic for an SE about Cthulhu mythos–based games, it follows that such questions are on-topic for a SE that is about all roleplaying games, including those Cthulhu mythos–based games.

So here's the heuristic I'm proposing:

• If a question is on-topic for a specific roleplaying game, it's on-topic for the Roleplaying Game Stack Exchange.

I know you're probably worried about questions getting bad answers because you're worried we're not expert enough in those sorts of questions. I suggest this isn't worth worrying about. For example, few people are expert enough in how Reign's Company rules work to give good answers, too. That doesn't make it off-topic—it just makes it special-interest. Rest assured that the people who are interested in a game will be expert in the things that are relevant to playing that game, whether it's the nuances of social life in Vichy France or the names of obscure pole-arms.

If the question is too hard to answer because it requires expertise we don't have, the system will take care of that for us. We don't need to police such questions. What will happen is that it will be low-voted, and hang around for months (or years). Then someone who is exactly the expert the OP was looking for will discover it, answer it brilliantly, and then the question will have served its purpose.

Essentially, stop worrying and learn to love the voting system. Give the system a chance to do what it does best.