Great points. I think showing all of them on a graph separated will allow you to see how each is affecting the overall sentiment. Being able to make custom feeds will also empower you to make your own weights.
Right now its crypto focused sites, but I find some of them to be positive leaning. Likewise the traditional finance sites seem to be negative leaning. My goal is to add source sentiment so you can see all the sources and which way they lean for all articles. You will also be able to filter the sources you wish to see. Quality of sources/articles are based on reading though the articles, comparing them to similar articles from other sources and making a determination whether or not its a unique article or a spin off another one.