Let Leona proc her passive
I don't like Riot forcing champions into specific roles by taking away abilities if they don't go into those roles. Leona's passive is literally useless laning unless she duo lanes; I believe this is bad design and would create more diversity if she could proc her own passive, without buffing her as a supp. If Lux can proc her passive, why can't Leona?
EDIT: This really wouldn't affect bot lane Leona I don't think; at the least be a very minor buff. However it would make top or mid Leona much more viable, increasing diversity. Ignore the Lux argument.