The NASA Spaceflight article Extended Russian EVA complete – conducts satellite deployments contains a very long discussion about the timing of the CRS-12 launch. Had it missed the "single shot launch attempt" it would have to be delayed by several days in deference to the upcoming Atlas V launch of TDRS-M.
Incidentally, there was an additional item of interest for Dragon’s ability to arrive within this short window of opportunity, relating to the communication systems on the ISS.
which is followed by a long, nine-paragraph discussion of redundancy of communications, the space walk, Dragon's arrival, Field Effect Transistor (FET) Hybrid failure and the Canadian robot Dextre.
I can't follow this article very well at all. There are issues of timing, redundancy and a hint of a possibly impressive number of things that could have been going on at once. But I still don't really understand the point of this. What happened, or what could have happened, that would be so notable?