Discussions Sith exodus- last days ofthe old empire, first of the new

There seems to be major discrepancies in the portrayal of the old sith empire at the time of Naga Sadow's leadership in relation to the sith exodus and founding of a new empire on Dromund Kaas. The old sith empire takes on a very unique appearance, from the ancient egyption-style architecture and armor, to ships and fighters that look almost like they were grown instead of built, with seemingly amorphous designs. However, during and in the few years following the exodus, the "style" of the new empire, with grey angular ships and Galactic Empire-esque uniforms and interiors, was already present. Here's some illustrations of what I'm talking about:

http://img2.wikia.nocookie.net/__cb20101213075839/starwars/images/6/69/Vaiken_exodus.jpg
During the exodus, where the signature "star destroyer bridge" design is already present. Also note the uniforms and mostly human crew.

http://img4.wikia.nocookie.net/__cb20120611150659/starwars/images/4/4b/Bioware_bellator.png
Assembly of a warship, estimated at no more than a few decades after the arrival on Dromund Kaas.

VS
http://img1.wikia.nocookie.net/__cb20110212110447/starwars/images/e/ef/Sadow_vs_Kressh.jpg
Note the armor, weapons, and the all-sith species crowd.

http://img1.wikia.nocookie.net/__cb20080926132539/starwars/images/9/9d/InvasionFleet.jpg
Sith fleet, no more than a couple years before the first photo, and considering the exodus fleet was nomadic and likely didn't completely revamp their ships and uniforms, about the same time.

What you think was the reasoning behind these differences? The suddenly change in species demographics? Uniforms? Ship designs? On another note, how do you think comparatively small fleet of refugee ships could grow into a seemingly vast empire with massive numbers of subjects, which until the Great Galactic War were virtually all descendents of the original refugees?

 

Is it possible they had something like the Star Forge?

 

Unlikely. The exodus fleet was gathered together by Vitiate (Sith Emperor) from remnants of the old sith fleet. He probably gathered a bunch of laborers and servants as the bulk of the fleet, which could help explain the human majority (though I don't believe there's any record of the old sith empire contacting humans between the exiles' arrival on Korriban and the war. Possibly a human settlement uncontacted by the greater galaxy). The ships were from the old empire however, and since they were nomadic the entire trip to Dromund Kaas, they didn't have the means or the reason to remodel their ships. If you look at the other images provided by the TOR history record books, you can see a ship very similar in design to the later imperial shuttle landed at the exodus base camp during their first arrival on Kaas.