..... is that if the engines were at a nominal approach power setting at 600', then even if they failed to respond at all until touchdown they would still have been at that same power setting, and the approach would have been nominal at least until the [attempted] power reduction before/in the flare!
Yes Intruder,
That is the sort of thing I am trying to get at too - hence the interest in how short the aircraft touched down.
It mayeven have dropped a wing at some point, and in the long run we may find that the 777 responded incredibly well to large control inputs, effectively at or below Vmc..
As FO Coward has said, he feared for everyone's lives at one point, so
I fear there was a point he felt they wouldn't get over the fence at all..
Having been around and seen the appalling results of the BEA Trident deep-stall out of Heathrow over 30 years ago now, and despite this accident's implications, I can really see BA's and perhaps Boeings phenomenal relief and need to applaud at an outcome almost beyond belief... all the work that's been put in to Pilot training - indeed their whole staffing philosophy and then the massive leap forward in aircraft design; crashworthiness, safety systems, general handling tolerance and robustness ... unexpected things will happen, but the outcomes have been mitigated this time. 
That said, we do need a new International airport - in East London, Thames Estuary - well overdue IMHO.