Here's another thought.
It seems like there is this repeating pattern, where they release the game, and then not enough people buy it, so it goes on sale within a relatively short period thereafter.
Then everyone who bought at retail price complains, because they feel like they have been somehow shortchanged ("early adoption tax").
This is obviously not intended by Stardock, and probably isn't the way things should turn out.
So what if pre-purchasers got some DLC for this "block" for free.
Then if it goes on sale, the folks who purchase at the sale price won't get the same value.
The folks who purchase during sale would have to but the DLC for the "block" separately.
SO no complaints from the folks who paid full price.
Sort of like a mini founders program for the loyalists.