So the sim is workin at least correctly on armors with DR<60% and that's enough to show that some weapons are clearly useless and like pointed somewhere else, assault riffle is the worst in the case. (since FN Fals will be revamped, i will not speak about them here). If we compare to 10mm SMG we can easily see where is the issue.
First with strenght, assault rifle have a 45 range, but the point with this is that if you play a burster, this won't help you much, if you play a sniper you prefere using a Hunting rifle, better to snipe and one tier lower (even the scoped version). So yeah it can be good to be half sniper half burster, but not sure it as any interrest in this, since snipers do load of damages with aimed shots, no need to burst.
On his weakness the base damages are really weaks for a 5APs rifle.
10mm SMG JHP avg 12.75 max burst 180 bypass 24 - AP avg 6.38 max burst 90
Assault rifle JHP avg 15.6 max burst 160 bypass 32 - AP avg 8 max burst 80
the 2 weapons do so few damages (against a simple leather MK2 JHP do same damages than AP on nothing) that you won't go for a single shot with those too since there are powerfull single shot weapons, and in burst the SMG is always better for 1 less AP to fire. Magazine are alike since you need to reload every 3 burst.
Now lets see how much damages a critter with BRF and 9AP can do in one round with each on a metal armor, since tier 2 should be ennemy of nothing uper than a metal MK2 (i won't oppose it to BA it would be a non sense)
10mmSMG AP 2burst and 1AP wasted -> 160 max dams
Assault rifle AP 1Burst 1 single -> 90 max dams
And 10mm SMG have even a greater advantages if you use fastshot too, the damage drop compared the 2 guns for a feature (long range) that cannot be really of any use is maybe a little too strong. Someone said put the accurate perk to AR, that could be a little strong, but yeah at least it would make something a bit different in the game, long range bursters, but i fear it become a second sniper style. (specially if XL70 have the same favor)
Or it's possible to raise damages simply to match better those of 10mm SMG, making AR fire 10 rounds in burst would do it, and the difference in AP to shot will still give a little bonus to 10mm SMG on close ranges.