Contributory causes
As ever a lot of useful comment on here. I have only flown one jet type with EFIS and liked it for mass info and ease of use but...it does take away the automatic scan that used to be the norm (and often disadvantage) of the old T panel and I feel that was a factor here.
I have had two ADI failures on conventionally instrumented aircraft and they were non events. It was instantly obvious what had happened without needing to think about it; even though one occurred in the first 500 feet of an IMC departure. The procedure to deal with it was also clearly understood - "ADI failure, you have control"and we carried on easily enough.
That the autopilot disconnected didn't help these guys either as they then used useful brain cells controling the a/c and sadly not in the best way but maybe the EFIS design was part of the reason why. The investigators seem to think so.
Bring back the scan as part of training procedures? Get into the habit of cross checking with the gyro standby during departure and approach for example, so that at least some form of cross checking becomes automatic.