One thing I say, something that shares one conciousness even if all of them are different can be quite strong. Just think it, all of groupmind shares all what they see, hear and feel, thats perfect symphony for war, no communications that can be interupted, they can strike anywhere and anywhen they want, becuse even if their scouts gets killed they know exactly whats happening where and when.
point of interest: this group minded-ness is instantaneous? what one shivan node/shell/body experiences on one side of the galaxy is already known to all nodes even on the other side or is there propagation of sorts? travel time could be used to have a group of nodes in a system act as one with an active (though not instantaneous) link to other nodes. the more nodes in-system the smarter the local set becomes. instant communication directly implies that the ability to tranverse that distance instantaneously is also possible... so subspace seems kind of limited.
data propagation times could also explain why it's possible to defeat shivan nodes at all since it as a whole would be instantly aware of everything... which does not seem to be the case.
Amazing that Terran and Vasudans were able to stop them from doing their purpose of universum, especially since StarBorns who are vastly more evolved and got caught pants down in Capella 
another point of interest: shiva is essentially fighting a war on 2 fronts. the overt war with other cold-life would, as far as i can tell from the mindgame premise, be akin to us eating breakfast. it's just part of their existence and not overly important to them. if they miss breakfast at home they can pick something up at the local store etc... the war with the starborn on the other hand is vastly more complicated as no direct action can be taken least shiva's hand be tipped. to that end in the original FS campaign the shiva should have known perfectly well that a) shields don't work in subspace and b) the terran forces were hot on the lucifer's trail. it
could be theorized that the shiva were aware that starborn would be watching this battle intently from subspace and in sol system so they allowed the pre-GTVA forces to
cause the lucifer's destruction, blowing the jump node all in an experiment to see if it would damage the nearby starborn in the resulting shockwave.
and on that note:
What's up with the Starborn and jumpnodes?
Imagine a stand of old-growth forest. Under the trees, very little light reaches the ground, so there is almost no underbrush. At the edges of the forest, where sunlight does reach the ground, there is a heavy growth of bushes and shrubs that acts as a barrier to the woods. If a traveler wanted to cross the forest, he’d first have to force his way through these bushes, so he’d search for a nearby thin spot. Once through the bushes it would be a fairly easy walk through the trees. At the far side of the forest, he’d again look for a thin spot in the bushes and force his way out. If he kept using the same route, the bushes would eventually stop re-growing, leaving a permanent hole in the barrier. There would also be a noticeable path in the forest.
i don't think this analogy quite fits the FS universe in that during the few missions that take place in subspace you are in what seems to be a rather well defined corridor leading distinctly from point A to point B. so your forest would need some internal underbrush to be worn out of the way by repeated travel forming the trail (corridor) effect we see in subspace. the jumpnodes themselves would remain as the border brush that has grown thick due to the extra sunlight.
this doesn't quite explain the difference between intra- (within a single) and inter- (between separate) system jump drive setup other than a plot device to save the player from having to dock with some mothership all the time. i suppose that would be a quirk in that the distances intra-system are so small that you can pop out and in again so fast that you really barely touch true subspace before you're already there. normal fighter subspace engines wouldn't be powerful enough to actually break the barrier but getting close enough allowes some travel.
/shrugs
further thoughts: if a human became aware of the game could they secretly contact the shiva or are the shiva so blinded by their programmed blood-lust that they wouldn't accept help? or prehaps they'd be too afraid that the terran would let slip to a sensitive and the starborn would learn of the shiva's duplicity. terrans are, after all, all individuals and the actions of one
node rarely syncronizes with the actions of the others.
opens the possibility for the shiva to contemplate genetic de-programming as a condition of the other coldlife joining into some short-lived alliance (shiva's part being "here's some info and we'll lay off killing you for a time") to stand up and say "sorry but we're not going to play anymore..."
or is it essentially impossible for the undeveloped terrans to act so without the starborn taking notice?
an out of the way, star-less void, far from any starborn-frequented subspace lanes would be a great place to find massive shiva structures conducting starborn-war experiments.
first post by the way...