My choices were:
Machine Gun = great anti-infantry, needs ammo
Flamer = great to send burning liquid around a corner, needs ammo
Small Laser = not good vs infantry compared to others, good vs armor, only needs recharging
SRM = plenty of range compared to the others, needs ammo
If I am removing people from an entire county, the amount and mass of of ammunition will add up quickly.
So my choice was the one that just needs the Battlesuits to come back to an Omnivehicle or Mech to recharge, then go back for more war crimes. If someone tries to hunker down then the Small Laser can be used to slowly burn through their protection. Once you have a single hole inside their protection you point the barrel of the small laser at the opening and let loose a few shots inside to deal with any survivors.
Ideally I'd want something with Pulse ability to improve anti-infantry ability, but for any sort of long-endurance mission I want an energy-based weapon. The only problem is that it makes me semi-predictable and opponents will tend to equip the Blue Shield (anti-PPC), and protect with
Laser-Reflecting armor.
Perhaps the vehicle supporting the Battle armor should have an artillery weapon or Gauss Rifle to deal with anti-laser armor? A Mech supporting the Battlearmor would have a melee weapon (and likely a Gauss Rifle too).