@Aush: details on the Sith
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They actually explained how they got their small fleet of vessels, it's just they missed a great opportunity to actually tell some of the tales on missions they actually took in getting them. It would have been very interesting to read and would have been a good set-up for introducing the readers more to the specific Sith characters.
The Sith Tribe is building this fleet just two years before the FOTJ stuff, so they haven't been around that long, and it's only a dozen ships which sound like freighters that they are capturing and arming so that they'll be war vessels. That in turn also makes me wonder how these Sith will ever be a significant threat. I can't see these captured ships being on par with a modern day Star Destroyer, and they don't have the numbers to take on the GA, so how will they plan on doing it? The only thing I can think of is that they are going to rely on Force powers in fleet actions. Or just doing really smart, precise attacks that will somehow cripple the GA. Of course, this is assuming they don't get wiped out before they even get a chance.