Leona needs quality of life buffs to her mana/regen/costs.

I wanted to compare some champions with similar playstyles. (That is tanks with damage reduction that iniatiate well.)

                                          Leona                          Nautilus                 Maoki      

Mana 302-982 334-1133 337-1108 Mana Regen 6.0-19.6 8.6-20.5 8.7-23.1 Mana Cost of all abilites 245-285 300-360 220+30/second-260+30/second.

Even more noticeable is that those other champs have enough damage in their kits to take a solo lane. Buffs bringing her mana and regen in line with those would be more then fair.