Renekton's having some bad times, so I'd like to propose a change to his healing.
47.50% winrate doesn't look too good right now, so I'm guessing the Preseason isn't helping him. As such, I think he'll need either some buffs or changes of some kind.
A change I'd personally like to see is to change how his Q heal works. Right now it's always a flat amount per enemy hit, which limits its power. I suggest that it be given a variable healing range depending on how low on HP Renekton is. Big healz when you're almost dead, weak healz when you're topped off.