I think the idea would be to have a calculator for how to get a kingdom most efficiently to the next star level. This might be a little complex, but here's the idea:
Assume troops are constant.
Option 1: Ask for number of traits that the player is willing to add as the independent variable. Dependent variable outputs are the total number of souls needed, and how many levels should go to which troops in order to get to the next kingdom level as efficiently (in soul costs) as possible.
Option 2 (more complex?): Ask for number of levels or souls the player will add as independent variable. Dependent variable outputs are whether or not the player can get to the next kingdom level with the traitstones owned, and which ones are needed for which troops to do so. Prioritization given to more common traitstones usage, minors > majors > runics > arcanes.
Hope this makes sense - it's asking a lot, I know, but it would be another amazingly helpful addition. Many thanks for the great tools!