There were 440 pounds of batteries on one of the cargo items. Fire seems plausible and might explain the alleged radar track to 40k feet. Alternatively other 777 have reported a fuselage cracking problem around the satellite antenna. Decompression from that could explain the dive to below 12000 feet , the loss of some communication ( if the Ping channel a different antenna?) and perhaps incapacitation of the pilots. But this seems less likely.
The most interesting thing about the Inmarsat anaylisis is that it relies on the dubious and odd radar track of the Malaysians that showed turns at VAMPI GIVAL AND IGREX. My theory was that these were mistaken reads miss attributed from SIA 86 another 777 at the same place and time. The Inmarsat people seem to say that the north south symmetry is broken by using that flight path. Yet this path makes no logical sense for an accident. It would have to be volition and shows control .
I'm inclined to go with accident still and thus don't believe that flight path. I thus don't believe the Inmarsat analysis that relies on that. But I do believe their conclusion that it went south.
The perfect correlation with similar flights they report is however a large fly in my ointment. It a remarkable coincidence this flight was so perfectly aligned with the satellites orbital track that it created this north south Doppler symmetry!