Thresh: Easy corrections to bring Balance
Thresh is a champion who causes a three second stun, and while stunned you're being pulled toward the enemy team. Once that's done, you're getting flayed.
Suggestion: exchange the stun for a root, so players can still attack while immobilized for this long duration. This is also more consistent with the idea of an extended chain wrapping around a leg, rather than a powerful blast stunning a target, or some magical runes restraining a champion. . oh, wait, that last one already is a root.
He causes so much CC, without even considering his ult. Which is a fun ult, in theory, but the walls of the box are too constrictive: they are guaranteed to break. I feel like the fun idea here, is that players can still use their moves, but are stuck in a tightly knit battle. Instead the box is so constrictive that literally almost any movement by anyone but Teemo will break one of the walls. That's just not fun, and isn't utilizing the idea of being in a box. Large characters can't even reliably flash past the thin wall without breaking it. It might as well be a slow to the first character that moves.
Suggestion: Walls are broken when the middle of the character touches them. This matches the theme of an ethereal box that can't harm you until you try to escape it.
Thresh also deals quite good attack damage. I have no problem with this, because he's using a scythe, and that's a good weapon for dealing damage. However it does lead to the question of what is Thresh weak at? He isn't so good at running away--but he's certainly not the worst at it--and in every other respect--including helping other champions escape--he's strong. There's some notion of balance in that he doesn't gain armour per level, but. . he does, because he's always going to gain souls every game.
Suggestion: Thresh should have to touch, or at least get closer, to souls to grab them. This opens him up to attack, and highlights his weakness of escaping. In my opinion, his stats wouldn't need to be changed, because counterplay will naturally keep him from becoming such an extremely potent tank, which he achieves extremely safely in the current build.
I feel these suggestions would create a more fair, balanced Thresh, without altering his playstyle. I think it's inevitable something is done with him. Right now, though, he's just kind of grinding with his OPness.