My own opinion is that sources are used to do something. For the most part, on Wikitree, to create a tree. And to create a tree you need to creat connections. So if a source creates or augments existing connections, it's useful. If it is useful for other purposes, like illustrating the changing mores of a society, not so much so. So in a WikiTree context, censuses are wonderful, particular in the US Censuses from 1880 on. They usually connect parts and sometimes all of two or even 3 generations of a family. The ages and places work to anchor the connections through various censuses. The same thing is true for Birth Certificates, Death Certificates and Marriage licences. This is why City Directories aren't so valuable since they don't usually have links (except marriages). Insofar as you can trust them, compilations like the SAR applications which Ancestry.com has can be useful. But they have some of the same problems as say Ancestry Trees.
Well to get to the main point, I think not having a source for a particular relationship is worse than having many sources for non connections when it comes to the WikiTree project. Knowing who a person's neighbors are or what a person died of or even what a person is famous is is less important. Now, everyone, including the WikiTree Leaders have things, often many things which don't hinge on the actual WikiTree goal, But when it comes to complaining of the lack of proper sources, I think the community interest should concentrate on connecting the profiles of people, and let the non-connection content reflect the personnel interest of those creating and embellishing the profiles.