I say Aymeric had the better development when it came to understanding him as a political leader. We got a good amount of time to understand his personality during 2.X, then we understand his political stance in Ishgard through 3.0, and we finish off his rise to being Ishgard current leader in 3.X which during this time he provided concerns about being picked as the leader with among concerns involving people's views of seeing him being maybe a puppet for the Eorzea Alliance or that him taking up position as the new leader of Ishgard may see it as another attempt for political power between family members. Of course in the end the majority of Ishgard voted for him as their new leader.
Hien on the other hand, we never did get much time to know him as a person, political leader, and his stance on how he will handle his leadership long term with any potential concerns he may have. It was rather rush to get him to being the new leader for Doma due to the Plan for causing a split in Garlean's Forces so we have a advantage in Eorzea taking back Ala Mhigo. However, as we have seen in Post-Stormblood events, he has been free to develop his country the way he intended without any outside influence. Of course the major problem he is dealing with mostly comes from the people who are far too use to the old ways of things and events involving the people of Doma who were conscripted into the Garlean Forces since the people have mixed feelings for those who became conscripted into the Garlean Army returning to Doma.
While she is open and honest, she does give me the feeling that she is "the last person the people of Tural will pick as a leader" trope type character. She does show some of those classic signs being fearful during certain moments that can end up fatal, probably not the smartest of the candidates, way too open for the more subtle game of politics, and way too ready to start a fight.