What happened to Leona?

She gets dumped on by Zyra, Brand, and Malz.

During the 1st IP Boost i've seen her in almost every blind pick i've done,and it was almost always a mirror matchup in bot (Mf+Leona on both sides), It's true that early laning poke destroys her,and so it's not so "free elo" as it was before,but if no one plays her it means the only remaining are good leonas (or those who don't care about meta and like playing her anyway) who can survive and stomp zyra and such,so good luck if you find her again.

check champion.gg and see: she has gone no where. Jumping the ADC's bones 24/7 like she always did.

She's still played you just probably don't see her cause everyone's busy running mage "supports" even with this meta she's still good but she can only do so much alone considering your adc is just gonna get trashed on no matter how badly you trash theirs. So you're better off just picking another mage and doing the same as the enemy

Leona needs a small buff to Hp, Armor and Magic Resist, but that could be addressed on the Tank update, so i'm going to hold off on any assumptions right now.

she got completely gutted in patch 6.14

the meta

Melee tanks in general aren't favored in the meta so you probably see less of her. She's not in any way bad, it's just that there's little incentive to pick them when picking mage supports like zyra and malzahar has so much value.