I’ve seen a number of threads where people are looking to have the same functionality to have a link back to an email using Omnifocus on the iPhone. While you can drag and drop email onto Omnifocus on an iPad to accomplish this, and use the clipper on the Mac, there isn’t any way to do this on the iPhone, short of using a 3rd party mail app. While you can use Mail Drop to email something to Omnifocus, it won’t contain any link back.
While I didn’t think this was technically possible, one thing I noticed in Things 3 is that when you email something into Things Cloud, it somehow retains a link to the original email in Apple Mail. No idea how they do this, but this certainly gets around the issue of not being able to get a link back regardless of what platform you are on.
On a separate but related note, Things also can just use drag and drop on the Mac to add tasks (in addition to the hot-key).
Would be great for Omnifocus to at least have the link available when you use Mail Drop/ Drag-and-drop on the Mac would be a nice bonus. Not sure if there are any plans to do this, but I’ve sent this in via Omni’s feedback, so here’s to hoping it gets on the roadmap.