stall + wake turbulence
Coming back to the wake turbulence:
I agree that there is generally no problem with wake encounters for a 737 when following other traffic - even behind a 757 on a reduced separation.
But was the ill fated flight on an ILS G/P? Probably not, as they hit the ground about 1,5km short of the runway.
As wake vortices are gradually descending, the struggling crew - as Belgique has perfectly described - may have been hitten by another problem, which made the recovery from a suspected low-level stall impossible.
Double trouble: Stall, extreme pitch and wake encounter.
Maybe no encounter that gave them a huge roll moment, just one enough to spoil the last bit of lift they still had...