I did up a quick mod that should double the damage of all missiles and non-manual ballistic weapons. It's untested (I don't really have the time for it right now) and is surely unbalanced.
While adding AOE to missiles might be possible, I don't have the time to try to work that out at the moment.
Here's the code (which you don't really need to see):
ModBallisticPerLevel overrides BaseSkillBallisticsPerLevel
ProjMinDamage 3.6 // Default 1.8
ProjMaxDamage 10.2 // Default 5.1
ModBallistic overrides BaseSkillBallistics
ProjMinDamage 12.0 // Default 6.0
ProjMaxDamage 24.0 // Default 12.0
ModMisslePerLevel overrides BaseSkillMissilePerLevel
ProjMinDamage 4.8 //Default 2.4
ProjMaxDamage 14.4 //Default 7.2
ModMissile overrides BaseSkillMissile
ProjMinDamage 16.0 //Default 8.0
ProjMaxDamage 32.0 //Default 16.0
To install this mod, simply download the attached .zip file into the "Assets" folder of your Drox Operative directory. You can adjust the values within the archive until you find a balance that works for you.