We decide first to change the minimum the rules, and to maintain as possible the fluff for every nations. We want every ship to be playable and fear by the enemy. And like this, if you want to be competitive, you can take as well the models you like and not only the ones the ORBATS say to take.
For us, EOTBS is the most average and strong nation, so for example we change them just a bit. On the other side, KoB was the lowest so there is a lot of change for them . Another example is RC where mortars are great but turrets are very low in compare so nobody is taking the turrets models. So we decide to improve only the turrets models.
Our way is to choose for every type of ship a reference (for example "assault carrier"). And we adjust for every ship with comparing : the reference , his nation, his fluff and some other ship we think there are in the same range.
As a result, we preferred to improve where something is not good , rather than to nerf a strong unit (and make angry some guys who love the way of playing this strong unit).