What's interesting is the I get better spacial imaging with my custom in ear monitors which is molded for my ears than my favorite cans. There are lots of talks of custom in ear monitors providing imaging, and I figures recording provide imaging of some sorts that headphones can pick up.
Maybe - I don't have any customs, so I can't really comment on that part. I can say though that the difference in realism and imaging between my headphones (Denon D2000 through an O2/ODAC) and my speakers (B&W 805s through a Denon 2808) was not subtle - the speakers did pretty much everything MUCH better. As much as I love good headphones, the soundstage and experience just don't compare to what you can get on good speakers, in my opinion (with the possible exception of a couple of amazing binaural recordings I've heard).