But...
Because a combat roll requires a figure not only to beat his opponent, but to also beat his opponent's armour on the same roll, it is a system that needs extreme results in order for combat to be decisive. You could use either 2d10 or 3d6, but by pushing the results to the middle of the curve, you will ensure that most combats end with only a few points of damage being done, or none. You could play the game this way, but it would slow it down considerably, with lots of fightings going on for many turns.