Most mechanical units are vulnerable to water, but this is not reflected in Heroes 5 in any way. If in Heroes 6 there were abilities that gave logical advantages and disadvantages, then here, there are none.
So, the question is: Would it be imbalanced to give all mechanical units a 50% vulnerability to water, but at the same time increase the power of "Repair" by the same amount?
И пусть Эльрат осветит твой путь