I fail to see how dropping NC/ND types from CC v4.0 would be a benefit.
The idea behind the Commons is that you have a set of resources that anyone can use at his or her convenience. In the digital realm, this refers to the set of works that can be freely distributed, modified, and you are allowed to create any service based upon them. This realm, lets call it the "free world", is huge: it includes Wikipedia, Free Software, and a plethora of other projects. The beauty is that you can pretty much take any parts of the existing free world to create something new, enriching the Commons in the process.
NC and ND are not part of this blessed realm. They form isolated patches of works that cannot be combined with the rest. They will never be part of the Commons. In that way, these licenses are not better than having no license at all. Or even worse, since they create distractions by leading authors to believe they are doing a good thing when in fact they are not.
So, if dropping NC and ND results in a single work being relicensed under a free license, this would be a benefit.