I think it would be helpful to have an obvious way to create an audit when browsing the source of a project from Diffusion.
Currently, in every other context in which I am viewing source, and I click on a line number, I am allowed to create a comment at that line - in Diffusion, this merely highlights the line. This is a rather confusing difference in behavior - I was confused for several minutes at first, and I know that I'm not the only one at my organization.
Ultimately, this would be helpful when reviewing a file as a whole, instead of a particular commit. For example, I just identified a problem in a particular pattern we were using in our unit tests when applied in a certain way. I'd like to be able to browse the source of my repository, and highlight places where this pattern has unfortunate side effects, and then assign the responsibility for fixing the tests amongst my engineers.