I'm a little bit apprehensive about straying into postulations (since posts have a way of haunting one) but just musing at the end of the day.
Accepting the reasonable explanation for one reverser deployed as stated in today's posts (one reverser MELed and the other deployed at first re-contact with the ground)
I am left with an aircraft either with insufficient speed or insufficient configuration to climb out of ground effect. A lack of speed has time to be noticed while a misconfiguration is a gotcha after you "set power" and if the gotcha is not annunciated during the takeoff roll then it is often a fatal flaw as NW255 and Delta at DFW demonstrated.
I do not yet see convincing evidence that too little speed was present (after all it did lift off in ground efect) although ground tract radar and/or useable DFDR data may answer this more positively
As in NW255 the DFDR would clearly show flap configuration and unlike NW255 it has not been leaked yet into the public domain.
Then there is the damage impact marks of the actuation for the flaps and slats and typically in spite of fire damage some of it remains on one side or the other to confirm their position at impact.
I suspect that people very close to the investigation allready have some very positive clues for and against many of the theories postulated on this board.