settlers-of-catan is a better tag then
Settlers-of-catan refers to the original game, but,
catan could refer to any of the myriad of Catan games. A question that pertains to the Catan universe could be tagged as
Catan, but I think those will be very rare. While our current usage basically only mentions the core game and thus one tag, more detailed tags would be better for if we get significant number of questions about the Catan games.
While I agree that when you first think of Catan, you're probably going to think of the original game, that's not gonig to be the case for everyone. Settlers of Catan has had three major expansions and other game series like "Starfarers of Catan", and "Catan Card Game" have been launched featuring the Catan name. If all the Catan games could be played together, I think one tag to encompass them all would be a viable solution. Since these are actually distinct games, multiple tags would be more precise.
Even the base Catan games plays very different then when playing with the Cities & Knights expansion. That's why I think
settlers-of-catan is a much better tag then just
catan. Now, do we need
seafarers-of-catan tags and
catan-cities-&-knights tags? Maybe not.