Don't get me wrong, 4A is pretty awesome - I leave it on all the time in winter. Electronics do pretty good job in 99% of the time. I also have HD Tow package which includes eLSD and I can say sometimes it kicks in automatically before engages traction control through the ABS/brakes, without need me to press a button to lock rear diff. All of that + Michelin Latitude X-Ice makes my set up almost bulletproof.
If I had to choose between 4H and 4A, I would take 4A any day. If I really need something extreme, I can go to 4L which locks transfer case in 50/50 mode without traction control, plus manually lock rear diff.
Some MT/AT tires could possible give you better traction in fresh snow, but nothing beats proper winter tires going downhill from a local ski mountain on curvy icy road...
The problem isnt that 4A is bad. The problem is that Ford sort of went backwards on the 4WD. All the older Expeditions have 2H,4A,4H,4L modes standard on all 4WD models. Why Ford removed 4 Low as a standard item for a 4x4 equipped truck is beyond me...kind of annoying you now have to look far and wide for what should be an easy to find option.