I understand personal preferences, it is very used word here.
But same is with shield+one weapon combination, you need also experience for that, maybe even greater then in case of two single handed weapons. In term of strength, shield + one weapon is much harder, so it is also much more difficult to handle instead of 2 single handed weapons. Also I disagree that 2 single handed weapons are only for heroes, in case of Khazad Dum veterans this combination looks great, so I really don't know why it shouldn't be used in case of regular unit. I think that be unique because only IH guardians will have this kind of weapons in dwarven factions as regular unit (beside Khazad Dum veterans ofc). Also when they got more offensive experience they will get upgrade of two handed axe which will have same armor effect in game. For me this looks very gradient and logical.
I agree two axes will make them look more dangerous but that is not reason they can't be disciplined Dwarven army. They will have proper armor and 2 single handed axes, for me that is more offensive unit, but disciplined one.
P.S. Bersekers are for me some half naked crazy units who are going to kill themself or destroy enemie, I really don't find this in case of proposal for IH guardians...