My idea which would make most logic would be this:
humans can use jetpacks and battlesuits, armor and helmets, all aliens can hold flag
thus mobility and armor issues are balanced, tyrants have lower def than bsuit but their hp is high, bsuit is the opposite, high defence, but same hp as always
jetpacks can fly, mauraders and goons can jump
drentches are fast, humans can sprint ( possible armor for feet which prevents light armor usage, but make human normal speed equal to drentch? )
for goons, when holding flag, they can still pounce, but not as an attack, kinda like if they swipe, it cancels out the pouncing dmg
tyrants can charge, but no damage is done either with flag
basically flag holder had no offencesive abilities, cause it wouldnt be fair to limit aliens to only a basa, while humans can use pulses and lucis with the flag, and the the basa is so weak, thats just way unbalanced.
so thats my idea for a balanced game