Hmm...you know, our lives would be a lot easier if the ships occasionally decided to make a rush for the large starbase from time to time. Just saying.
Even if that would put a serious dent in the number of available nebula hostiles. They can still shoot at small starbases while diving into the large starbase. So I don't think this is a good approach.
Reducing the size of small starbase production death spawn is definitely a good thing.