A naked human with a rifle is easily able to kill a tyrant in his base.
A dretch or a granger in their base needs a lot of suicides to kill a battlesuit user, feeding said user.
I think this is a problem. A solution to prevent that would be to make poison ignoring armor. Actually, it deals 5 damages per second, reduced by torso's armor, which means... 1 damage per second to battlesuits, and 2 damages per second to medium armors. It's barely helpful against human players...
I would propose to reduce the base damage to 3, but have it ignore armor so that in their base, lower alien forms would be able to fight back. Unlike humans, they would still need to reach a special building (tactical target, then) which does not makes it necessarily easy, but at least being alien with broken defenses does not means you need a full wave of kamikazes to kill a single battlesuit user.