this is probably my bias for nubia speaking & influencing this thought process but, i never want diana to be queen of the amazons, even with her mother's passing and the exception of others to pick up the mantle. she's much better as what she debuted as: hero, champion of justice and equality in humanity. she still serves as princess, has a duty to her people, attends council meetings, rituals, greets new amazons from the well of souls, etc etc etc. but she is not in the position of absolute power. i'm not saying / implying she can't be queen, or wouldn't be a good queen————i think she would be a great queen————but spreading herself too thin would cause things to slip through the cracks. she is already princess of themyscira, wonder woman, public figure, justice league member, god of war, ambassador of peace, the list is never-ending.. i truly do not believe the world, the amazons & more notably, diana, would not be able to handle the off-chance that a slip up would lead to something catastrophic. additionally, i do not think she would want it. the crown was her mother's. it will always feel as though she is trying to fill someone else's role & she wouldn't be able to make it her own like she does as wonder woman, ( or as nubia does as the queen of amazons ).
note: diana she holds her title as princess of paradise island, as does donna.