Even if the icing was severe, there is something missing in the puzzle. Dash's operate in pretty bad conditions around the world and I find it hard to guess that this one just build up ice and tailplane stalled into a house...
Of course you are correct in questioning this further.
We do need to evaluate all the possible holes that may have lined up.
There is a always possibility of a system failure and even a possibility that the pilot response/training for this operator did not accomodate this level of buildup.
and there is the possibility that it wasn't tailplane ice.
I'm keen to keep reading the NTSB releases, They are quite interested in preventing the next icing accident (this year, this month) and I'm sure that they will be working this issue.