I get Riven, I kind of get Fiddle, somewhat get Annie. But wtf @ Leona?
Riven does NOT deserve any nerfs. The sheep are getting her nerfed. Leona is just ridiculous though, bonus armour/mr that scales by buying armour/mr and high base damages + bonus damage if an ally hits the enemy after she uses an ability. That's pretty strong in a support, just look at Taric, he got nerfed pretty hard for just doing damage.
"They can't backdoor when they're coming through the front door..."~Me Nami is my waifu