Overall they need a visual overhaul as far as their weapons go and a logic overhaul for how they act. If they are assault troops they should really be using lighter weapons anyways and maybe have their melee always active in some cases (recon las guns, melee + las pistol, melee + auto pistol). Generally they shouldn’t be taking cover they should be laying down suppression and actively approaching till they can get in melee with you.
Even then i think it would make more sense for them to do what the captain similarly does and maybe get a few melee strikes in, pull off, use the sidearm if you are too far back or charge back in the with melee.
I really can’t tell the difference half the time and mostly just go “yep, it’s another shooter” and pop them. Hell maybe make like 1 out of 8 throw a smoke grenade at you so they can approach while covered.