Seems like the site would be dominated by this. Are trivia questions appropriate?
Who was the all time home run leader in 1950?
How many times was Joe Montana sacked?
Did Carl Weathers have a football card?
This may be an awkward "early beta" to flesh out. Most of the sites we created are for the "practitioners" of the craft (e.g. programmers, cooks, photographers). They don't typically mix with the end-user enthusiasts (e.g. software users, food appreciation, art collectors). We create separate end-users sites for them (e.g. Apple, Android) because they are not the same audience.
The top questions of Definition would seem to bear out that the "Sports" proposal is about practitioners (those doing these sports) and those with an interest in the sport itself (rules clarification, history, etc). I'm just not sure if that mixed scope would extend to the fandom.
It may be a self-correcting problem though — Once you eliminate the trivia, any question too localized in time, and "not constructive" discussions, what is really left? None of the examples you posted would qualify. I'm hard pressed to think of any that would.