If hypothetically stuff like nightvision and M41A/2s were standard issue for the marines, (alongside whatever else would be considered more funding like a tank every round.) What buffs would the xenos need in order to not get stomped?
Making death permanent for marines? How crazy would xeno abilities have to be?
As said, just HEAP would do the trick. Xeno health/armor would have to be buffed so much that HEAP becomes as usefull as slightly buffed regular pulse rifle ammo. SL-tier NVG is meh, tank is also not that good.
Tbh, if HEAP is available it would be musket firing lines from marines since HEAP shred any xeno, beside queen and king and maybe crusher front shield. Marines would need no chungus to stun or light armor for speed, since why do anything else than “hold lmb till horizontal” from 7 tiles away.