grizzled I am not immune to any well reasoned hypotheses but having just read Tim Vasquez's analysis again, he draws the conclusion that whilst nothing can be ruled out, there is no evidence of significant or extraordinary activity in the ITCZ that night or any unusual updrafts. His diagram at fig 13 shows the 447 just through an area of suspected updrafts but he also notes that updraft strength is generally lower in oceanic Cbs than overland Cbs.
That said, if I experienced a sudden and dramatic updraft I would likely put the left wing down and try to make a descending 180 .. which perhaps tends towards the "turnback" theory popular a few thousand posts back.
As you say, roll on the FDR & CVR being found ... it's surely only a matter of time.