Maybe the Empire was going to create more than just one Death Star to have. Maybe the 2nd one began construction a few years after the first, if in RotS, we see the beginings of the first Death Star. Maybe they were making it a normal rate but the Emporer needed it done sooner because of the whole first one being blown up. Thus, he would get angry for it not being on schedule and such. It seems perfectly reasonable to be an explanation. And its not really that hokey and would add to the whole fearing the Empire thing. That whole strength in numbers thing. This might also lend a little more credibility to all of the death star-esque stuff that showed up a little too many times in post RotJ EU.