first, i'm gonna let Dustloop define "zoning" so i don't look like a fool for trying to say my own version of what i think it is: "Zoning is when a player controls an area or space on the screen in order to limit an opponent's options while maximizing chances in creating their own. Old-school zoning incorporates long-ranged normal attacks and a projectile (think Dhalsim and Guile from Street Fighter 2), while new-school zoning can employ short-ranged normals with obscene hitboxes and quick recovery frames and numerous projectiles to make their opponents' lives a living hell (re: Venom from Guilty Gear, Lambda-11 and Arakune from BlazBlue). "
overall, i think the best zoners in the game go as follows: 1. Sinestro 2. Nightwing 3. Cyborg 4. Raven 5. Deathstroke
keep in mind, this is my personal opinion based on playing the game with them all to see who can adhere to the definition above the most closely.
Make me respect you! trust me i want to! :) YOUR FACE! GODDAMMIT!