To further the rock/paper/scissors of the weapons types, where ACs and the Gauss Rifle get penetration, missiles get fragmentation. Fragmentation does extra damage to non-battle armor infantry, civilian vehicles, VTOLs, and ASFs. Artillery, MGs, and LB-X cluster ammo also gets fragmentation. ACs can fire flak ammo, but lose penetration when doing so. Fragmentation doubles damage to non-battle armor infantry and civilian vehicles and double again in the open. ASFs and VTOLs receive +1 damage per cluster. So an LRM 5 missile cluster would deal 6 damage to an ASF or VTOL. Similarly, an AC/10 firing flak ammo would deal 11 damage and an AC/2 firing flak ammo would deal 3 damage.
Lasers get inherent accuracy bonuses to hit by ignoring some of the target's movement modifier, probably the first 2, representing that you only need to be able to see the target to hit it. Pulse lasers would simply ignore more of the target's modifier, up to 4 maybe. Note that the movement modifiers table would be rescaled for 2d10, so the bonuses aren't as big as they seem, statistically.
PPCs, plasma cannons, inferno missiles, and flamers would all get thermal/fire damage. Non-battlearmor infantry take +5 damage and double damage in the open (including doubling the bonus damage). For battle armor, calculate the damage as though the battlearmor were infantry, and if the damage exceeds armor plus trooper inside, the poor schlub cooks. So a PPC will deal 10 points to a trooper, but check if 15 would kill him. If it does, he cooks. Infernos would deal 5 points of heat damage, so normal elementals with 10+1 would survive 2 hits and cook on the third. A flamer would deal 2 damage, but check for killing the trooper on 7.