A caveat - when you quote from the WSJ, remember you are quoting from the WSJ - its track record is not brilliant.
I'm not sure if this Der Spiegel text has appeared before as I tend to follow Tech Log more, but I found this of interest:
"Until now, it appeared that the crew of Flight AF 447 had steered the plane directly into a severe storm that eventually caused the speed sensors to ice over. But the flight path recorded by the black box reportedly shows that the crew had been trying to find the safest possible path through the storm front. They initially appear to have succeeded as the flight data doesn't contain any evidence of more severe turbulence."