I can’t get the super ability.

For each learned skill, you can learn one ability within that skill's branch. For example, if you want to acquire empathy in the leadership branch, and you only have the basics of leadership learned, you can get diplomacy, but not empathy. You need at least advanced leadership and the diplomacy ability. If any of these conditions are not met, you will not be able to acquire empathy. Moreover, if you have already learned as many abilities as you have skills, taking into account their levels, you will not be offered any abilities during level-up, only skills (the exception is the Commander's Aura, which is always offered as soon as all the necessary abilities for it have been learned).