Just played a match as adc leona, now before the meta monkeys come beating down my door, it was an accident(thought i was support). i went full ad and attack speed and got s-. We had a bad start with 2 dcs but we bounced back hard when they reconnected. i went 14/11/13 with 198 cs.
Well, the S- is not surprising. You did more damage than most leonas. There's nothing stopping a full ad or ap leona from killing someone. I can easily see leona filling almost an assassin role. But nothing beats a ranged glass-cannon dps carry. And seriously, according to lolking everyone in that match was bronze 5. You could play anyone in any role and be successful.
The point of the ADC is to melt turrets and the enemy frontline (typically tanks) leo is melee range, so if shes meleeing the tanks and shes full ADC then the backline+the tanks can screw her over, plus she can get poked off turrets easily, she cant poke them. Leo ADC is definitely not viable (unless its bronze I guess).
