You can clearly see that, in the Freespace1 incursion, the Shivan armada was at that time undergoing a generational advance technologically, and by that i mean;
You'll notice that the FS1 Shivan Capital Ships, namely the Cain/Lilith, and the Lucy, all exhibit very similar componenets. The underside of the vessels are essentially the same, and the presence of 'Prongs' on both models further indicates similarity. Now, in terms of fighters and bombers, the SF Scorpion and SB Shaitan in particular exhibit the same blocky-style contruction visible in both the Cain/Lilith and Lucy models.
Looking at the rest of the fleet, the Demon stands out as quite a different design style aesthetically speaking. The spikes/spines along the ventral port & starboard edges do not appear on any other ship in the Shivan Fleet, prompting the idea that said Fleet was - at the time - undergoing a generational shift technologically speaking; moving from, say, 1st Generation Shivan Technology, to a spikier, meaner-looking 2nd Generation Shivan Technology.
This '2nd Generation' of technology is shown all but fully implemented in the FS2 incursion. Under the assumption that these are indeed the exact same Shivans as in FS1, thereby barring any arguement of different tribes/species/regional blocs of Shivans, it is clear that Shivan Technology by 2367 has almost completed its 'update' if you will to their next Generation of technology.
This shift is shown by the new, unique designs of Shivan Ships that pour out of the Nebula, exhibiting far more spine-like constructs on the outer hull, and an overall more juxtapositioned design. This is especially visible on the SD Ravana, which is nothing at all like the designs of the FS1-era ships; all semblance of the styles seen on the Lucy are gone, leaving instead a seemingly random assortment of large Spikes, an irregular engine design, and a non-symmetrical hull, something that really stands out in the FS Universe. It is obvious that Shivan Technology had undergone a complete restructuring of not only their technological style, but also a complete overhaul of their capital ship aesthetics.
Even the fighters of this re-designed armada exhibit this advance. The clunkiest fighters and bombers of the FS1-era Shivan, ie. the SF Scorpion & SB Shaitan, are no longer present, replaced by the sleeker, meaner looking SF Mara, and SB Nahema, both of which show considerable use of the Spine/Spike design, further emphasising the prospect of a complete Generational Overhaul of their fleet that was already underway when they stumbled across Ross 128 in 2335.
Indeed, this process to a new Generation of Technology is obviously incomplete, evidenced by the continued use of the old Cain and Lilith designs. But the sudden upsurgeance of this new, Chaotic Insectoid (possibly even Arachnid) build-style demonstrates that the Shivans as a species can alter the aesthetic qualities of their ships somewhat quickly.
As such, I personally implore model-makers to break free of the clichéd Insectoid/Arachnoid-From-Hell look, and instead come up with your own ideas of what Shivan Technology would look like in your own mind, based on the entire spectrum of Shivan Ships aesthetically...rather than simply churn out the Spiny, insect-like abominations i've seen multiplying as of late...
