|You can pretty much build a starbase anywhere. However, in 1.0X and earlier, you have to have them be at least 3 tiles apart on the map (this is going to eventually be changed to X number per sector -- probably 4 which is what the AI is stuck with).|
The way it is set up now seems to work pretty well. If you move to just having 4 per sector, you would be able to spam a specific area with 16 starbases by having all of them in a corner of a sector.
This would make sense if the star bases only influenced that sector (like GC1 if my memory serves me right), but the starbases influence an area around them, not just the sector. So having them a certain distance apart makes more sense than having a particular amount per sector. (Although changing that in GC1 would make sense.)