TV Chart offers an interesting bit of data smushing. It presents a sentiment graph of TV series, showing viewer-rating sentiment about each episode. Or at least, of the type of viewer who is inclined to rate each episode at a ratings site.
Their Babylon 5 Chart is not at all comparable to a good ‘view or skip’ guide. To be made more useful such charts probably need to have a toggle to ‘see the data adjusted by a panel of expert fans’. And then the option to save out a handy view/skip list.