So hey Riot...Leona has been really strong for like...forever...

I'm going to have to say no to this, as a Zyra main, Zyra dominates over her in not lane due to the immense poke. Take over bush control and focus your poke on her before engagements. I'm sure if she land on you before 6 you have to burn summoners, but do what Zyra is made to do. POKE THE HECK OUT OF LEONA AND HER LANE PARTNER. Force them to back, dodge that zenith blade. Leona is useless if she doesn't go even due to her all in dedication. Sure the ult stuns, but Zyra can do the same from behind in a larger diameter with the knock up. If anything, Leona is fine where she is at. It takes some communication on bot lane to get things rolling. And once you get a kill bot, her role is now to roam and help mid if she can/get those deep wards in. Otherwise, going even would not benefit her as her lane opponents aren't denies gold and have the items to take her down.

Another way to play against Leona is the same way you play against thresh.