I haven't had the chance to read all the posts but these are a few of my observations.
With my operator all icing aproaches on the Q400 are flap 35 and only 15 knts is added to the Vref not the 20 Kts as mentioned by others.
The barbers pole is only useful to show how close you are to the stick shaker. So as shown in the NTSB video it showed how close they got to the stall flap 5 and eventually stalled at flap 5 even though flap 15 was selected at nearly exactlly the same time of the stall.
I also noted that the captain reduced power in level flight whilst also selecting the gear down. That makes no sense at all.
And as for the F/0 selecting flap 0 as they entered the stall and increasing the stall speed by God knows how many knots, need I go on.
As I see it it is down to lack of situational awareness, a lack of adequate training and experience on type.
The Q400 is a challenging aircraft to fly well and I fly with FO's who have come off regional jets and a majority of them enjoy the new challenge.
There are a numerous number of possible slip ups operating the Q400 but my company knows the Q400 extremely well and the training is excellent.