I never understand why add-on's are not just added to the main game rather than separate, as is done in Trinity. The way Stardock have done it requires three plays of differing quality. How many buying Trinity will play the bare bone Sins? Few I think.
Perhaps because having expansion packs (which cost money) give the developers an economic incentive?
And perhaps because some who aren't willing to pirate would rather test out vanilla Sins first to see if they like it before paying $10 more for the expansion?
Also, good job bumping a thread more than a year old.