Fixed Thresh
Added counter play to his Lantern. Pick one: Enemies can destroy lantern with autoattacks, or enemies can grab the lantern.
Remove his insane early game damage: Either nerf his E passive or simply get rid of it, there's really no reason for it to be there.
For the love of God, fix his ridiculously deceptive hook range/width.
You don't even have to do all of these. Personally I'd be okay with just the lantern idea.