You know, looking at the Juggernaut… To me, it almost looks a little like a walking wood-chipper. Maybe that’s what those pipes are for? It scoops up a soldier, or a fellow beastie, and it “mulches” it into new mist, and/or some nasty area-effect nastinesses.
I’m kind of in favor of this, more for the visuals than the tactical sense, although I think that both would be reasonably solid…
They also resemble tube-worm shells, though, and It’s hands kind of look like something might be going on with them, as well. Could be some kind of tentacular/tube-ey effect going on there? Maybe it’s a grabber, and it also lays down some kind of movement-impairment stuffs, to make rescuing grabbed soldiers more erksome.