Let's look at the idea that the plane's anti/deice system was overwelmed by conditions...even similiar to the ATR 72 over Indiana that crashed.
If the plane was on autopilot, and assumed an unusual attitude of some sort in an effort to achieve commanded instructions (speed, climb rate or whatever)...the pilot might have thought something was wrong with the instrument, having never seen this situation before.
I understand the wing is more laminar flow than previous small citations. I couldn't find out what the anti ice system is, except for boots on the horizontal stabilizer.
can you imagine the autopilot pulling the plane into a stall, then holding it there while the thing spun in?
always in icing conditions in any plane, a hand on the stick might tell you more about how the plane is flying than anything else.