So a slow Marksman? How is that even expected to work?
To me that's just a horrible idea, he's either going to be too weak to keep up with other adcs due to being slow or end up like graves and 1 shotting people because they gave him too much damage to compensate for speed
Caitlyn at the moment is the slowest attacking adc to compensate for her damage / harassing and is probably one of the worst adcs in the game right now. Not to mention you gave "the slowest adc yet" a reload..
I don't usually say this about new champions but this guy is going to be either insanely overpowered or stupidly weak that will get buffed into being overpowered, you're just giving yourself a huge balance problem here with this guy