IMDb already has something similar to what you suggested, movie connections.
The link to this page is on the left if you are viewing the combined view (Always display full cast and crew credits). If you are viewing the partial cast and crew view, the link will be on the left under quick links, explore more with the link "Connections".
I can't believe that I have to make like two or three clicks to see the other films in a series. (and even then, still not very easy-to-read format) Every time I open an IMDB page I am surprised that sequels are not right up in the first info box, easy to read and easy to click.