Well it depends on if research is needed to build mining colony ships, but if not then I am going to blitz my neighbors and take out their mining colonies. If I can keep them pinned down long enough the attrition will give me time to build a fleet to take their primary colonies/homeworld which should give me a large enough strategic advantage to win.

As it is the speed which ships move at is a huge bonus for someone looking to blitz. Going for combat ships before harvesters doesn't really slow down production because with the new claiming system we will have fewer mining colonies anyway and while I am waiting to build harvesters the resources will stockpile.