I think ranyair is quite right but the elsphant in the room that so many are ignoring is that the pilots 'forgot' they were at TOGA thrust and failed to hear/notice they were approaching warp speed.
No way on earth could/should Boeing designers have anticipated anything as far off-scale as that being involved when they made their - imho entirely appropriate and correct - asessment of the action to take, action that would without any doubt have saved the day.
Neither can Boeing really beheld accountable for designing a trim system that becomes too heavy to use beyond Vmo as no one expects it to be required to work massively out of trim at that end of the envelope.
You can't design an aeroplane to cope with every imaginable (let alone all but unimaginable) foul-up a pilot can possibly make.
As to the lack of CVR, one can only surmise why such vital info has been left out. If the pilots had reacted properly and professionally there would be no excuse whatsoever to withold this, indeed the presentation of a coherent and rational response to the event would amply demonstate their pilots, procedures and training in a good light, thus the implications of it's absence seems pretty clear.