The post by F111D (re: Andy Pasztor article) does support those of us who favour the slush/icing theory for the crash.
It is a theory that goes a long way to explain the following:
* near simultaneous loss of power in both engines. (a critical factor that all theories need to explain and a severe limitation on most.)
* slight differences in conditions in each fuel tank can explain the slight difference (seconds) in response.
* why the engines responded properly to start with then dropped down to a thrust level somewhat above flight idle shortly afterwards.
* fuel pump cavitation (from slush retarding fuel suction)
* minimal remaining evidence (remaining slush would melt)
* if slush was mostly sucked out of the system prior to the crash, it would also explain why the fuel would test within specifications. (Jet A-1 Chinese equivalent Jet Fuel #3) It probably wouldn't have taken much water content in the fuel to cause problems if it was in the right location. All (or most) of the water would have frozen out at the temperatures in the fuel tanks and migrated to where it could cause grief.
I don't see any notes in the last AAIB update about EICAS warnings (fuel pressure pump or fuel filter clogged) as noted by CONF iture, although it isn't clear that they would invalidate the theory if they didn't (or did) occur. The AAIB report notes that the high pressure fuel filters were clean after the incident.
It also doesn't rule out there being other factors involved, but it explains events reasonably well without them.
I think that the reason the next update is taking so long is that the incident has a number of subtle causes. AAIB needs to make very sure they have it right. If this theory is correct or mostly correct it could cause huge changes in procedures in long haul flights in extreme cold weather as well as have the potential for other operational or aircraft design changes. If the cause was simple and straightforward, the AAIB would most likely have let us know already.