If Goku was a Champion

Innate - Superhuman Speed: Goku's attack range is 125 but he can dash to targets up to 450 units away. Goku's attacks deal bonus physical damage based on how much distance he traveled.

You are Rengar and the world is your bush. (Of course, the range here is a lot shorter than Rengar's leap).

E - Explosive Wave: Goku's pushes all enemies 400 units away from him, also dealing damage.

This forms Goku's main combo: dash attack, E, then dash attack again. Also his main way of disengaging.

W - Kamehameha: After a short windup, Goku fires a Ki blast in the target direction, affecting a wide area for 2 seconds. 800 range.

Can't have Goku without Kamehameha. This pairs well with E, you push a target away from you and then blast them with lazerz.

Q - Quick Punch / Leg Sweep: Each cast of this spell alternates between Quick Punch and Leg Sweep. Quick Punch is a punch in the target direction that damages the first target struck and applies on-hit effects, Leg Sweep is a kick dealing AoE damage in a semicircle.

This just rounds out his kit, it's a low-cooldown spell so he can deal sustained damage at melee range. Can be cast during his dashes to benefit from the bonus damage of Superhuman Speed.

R - Super Saiyan: For 15 seconds, Goku becomes a Super Saiyan, gaining 20% damage reduction and (20% tAD) bonus AD for the duration. During this time, the range of Superhuman Speed is increased to 600.