Anyone Miss Their 5D (I, II, or III) after getting an OMD?

I got a 5D2 as well plus 16-35L II, 50L, Sigma 85 and 135L.

While m4/3 is a great system, it cannot cover every desire. It can never give me a shallow DOF in wider angle shots. If I want to separate a subject from the background the larger sensor helps a lot.
Also low light quality is noticeably better on the Canon. Everything above ISO 1600 is just better on the 5D.

Having said that makes both systems complementary to me. I wouldn't give up one over the other. I take m4/3 whenever I want something small and light weight. If I purely want quality or low light I take the Canon.

For some people it might though make sense to give up on Canon. That really depends on how they use them and what their main subjects are.