In the past, I’ve found doing this sort of dependency-graphing to be very useful for figuring out where modularization in a large system needs to be applied. And it’s not very hard to do, based on ocamldep output or other dependency information that already exists.
On a lark, I wrote something that did this for installed findlib packages:
I mention this not to plug the tool, but rather, just to note that it’s really easy, and yeah, people should avail themselves of this more.