No particular reason to think the crew didn't know the visual requirements, per SE, but pretty clear they were unaware of their vertical situation. I say this based on no calls for 500 ft, approaching minimums and minimums.
....... and not verifying the step down altitude at IMTOY too.
Most of the approaches they flew were to 200 ft DA at 700 FPM, this one to 560 HAA at 1500 FPM, so things were happening faster than they are used to. The VS mode is no help with awareness. No automatic call outs, yet AP coupled and the crew missed their required calls. They apparently didn't even look for visual cues until the sink rate alert. Behind the airplane.
I agree completely. But bear in mind that the sink rate alert and their emergence from cloud occurred pretty much simultaneously. See Table 9, pages 28 and 29 from
http://dms.ntsb.gov/public%2F55000%2...2F550789%2Epdf