I don't even know if that's something that already exist (if so, it's hiding somewhere I didn't find even though I've been searching for it forever).
We should be able to click on something on someone's profile and see all the TV show that person is watching/has watched. All of them. Not only the latest episode watched, not only the latest TV show followed, all of them.
Also because this tool, I want to use it not only to keep track of where I'm at, but also keep track of stuff I've watched. Please, pretty please.