Its all speculation .
Not sure about 737 but if missed approach is not at threshold then can a fully managed approach be done ? Should it be in a selected vertical mode ? If the A/C was low on app , had visibility problems due to unexpected rain shower it may have gone wrong very quickly . Engines not powered up due up drafts / shear maybe speed brake left out ? Got visual , to low , pull back , no power up or to much drag and splash .
How ever it happened its great no one died so have to be thankful for that .
Hope the authorities work out the underlying factors and use it to improve their industry .