The stabiliser on the 737 has caused issues before on GA, particularly with a dual coupled approach and trimming back for autoland, (Thomsonfly BOH one example) this with the addition of ice plus pitch power couple is not a nice combination, it looks like they went around too high for the dual AP to have started to trim back, however many carriers load the -800 with a rear CofG for fuel efficiency reasons, this could all add up. Anyway all speculation until we see an accident report. My thoughts with the families and friends.