Champion Concept: Apache, the Attack Helicopter.
I have no idea if this kit is possible to balance, but I purposely did not include many numbers in the description to avoid accusations of making a massively overpowered champ. The W would probably be the hardest to implement, but with Yasuo and Braum existing, it just might be possible. I hope you enjoy!
P: 30mm Armor Piecing shells Basic attacks do some percentage physical and some percentage true damage. Only the physical portion can critically strike.
Q: Hellfire Missiles Fire two auto targeting missiles which prioritize champions. 2 missiles hitting the same target do less damage.
W: Chaff Release a cloud of chaff which persists in the area cast for a few seconds (duration scaling with ability level). When a projectile enters the area, it changes direction and loses its targeting if it is targeted.
E: Rocket pods Fires a stream of rockets in a certain direction which explode in an area of effect when they hit and enemy or upon reaching max range. Apache can move but not attack or cast other abilities while firing rockets. It would operate like Lucian ult.
R: Spray and Pray (Toggle) Passive: Apache stores fuel when Spray and Pray is toggled off. Active: Apache consumes fuel every second to gain a large amount of attack speed and movement speed but lose attack range and the use of damaging abilities while Spray and Pray is active. If Spray and Pray is toggled off with less than 25% fuel, Apache will be slowed when it is toggled off, scaling higher the less fuel Apache has.