Apologies for the delay in answering - this is work in progress!
First a link to a magazine articles on Edition 4 of the EMC standard.
http://www.mddionline.com/blog/devicetalk/what-you-need-know-iec-60601-1-2-4th-edition-02-22-17
Also, a 'white paper' from one of the big test companies.
(Free registration required)
http://www.intertek.com/knowledge-education/medical/iec-60601-1-2-edition-4-wp/
And attached are some brief notes I have put together. The comparison table in the original post is as good as anything so I have
stolen borrowed it.
Whilst the table gives details of the test changes the big change is in the overall approach to the testing. Although the 2007 version (Edition3 of the EMC standard) mentions risk and risk management this new version uses risk and risk management throughout and extensively. As 60601-1:2005 was a fundamental change this EMC standard similarly puts risk at the centre of how the tests are conducted.
For instance, in the 2007 standard there was a clear distinction between "Life Supporting" devices and others, with more stringent requirements. That distinction has gone. But that does not absolve a manufacturer from the higher requirement - instead they must use the Risk Management process to decide what is required - if necessary going beyond the specified testing.
This all means that the manufacturer must be fully involved in the planning of the testing. There is now a defined requirement for a detailed test plan to be in place before any testing happens. And, having spoken to one of the large Test Houses, they will require your Risk Management File before testing.
A complication of the introduction of Edition 4 is that different regions are now using different versions. US FDA will now expect new submissions to be Edition 4, whilst some regions are still using Edition 2 (2001). Whilst in Edition 4 the concept of "Acceptable Degradation" is included (as a temporary phenomena during immunity tests) that may not work within the pre-defined compliance criteria of the earlier versions.
