Since porting weapons straight from Shadowrun 4 seemed so successful, I'm looking at armor with that same eye. But immediately upon seeing armor stats, I see there's a problem. Armor ratings in this edition of Shadowrun are high. This is because armor is something you roll in this game, and on average 1/3 of the dice you roll will be successes.
I don't want to roll armor. With an eye for minimizing opposed rolls, I'm going to make armor a static number. Still, Shadowrun's a fully tested game, and its armor rules were written to work with its weapon damage codes, which I took whole hog, so the idea of abandoning the material completely leaves me thinking I might be pitching a lot of material already written for me.
So if 1/3 of the dice come up successes, why not cut the listed armor ratings down that much and use the resulting number as the static armor value in my game? Another quick glance says there's going to be a lot of rounding and judgment calls for this, but that's okay.
As for the impact/ballistic divide, I always thought the reason for this was so that melee weapons, which routinely do less damage, could still be viable. Since most melee weapons seem roughly on par with firearms for damage now, let's ditch impact completely and make armor a single value applicable to all incoming damage. Simpler yet.