[Alneyan]

ER is limited because it has no use in the game, since it merely alters Happiness and Reproduction at once. Five points in ER increases Happiness and Reproduction by one point, and vice versa when reducing this characteristic.

In the vanilla game, its only use is to provide with "free" points by lowering Environmental Resistance to 51%, while increasing Reproduction to 108% (or 109%) to offset the penalty to Reproduction. (Raising Happiness itself has virtually no effect)

All the other characteristics are limited to other values when decreasing, but you will likely not want to go to lower them too much. What are the characteristics that you would like to lower more than what you can do with the AIC mod?