He's a caster, much closer to a mage than an adc, and that's fine, but he still is a bit underwhelming overall.
I think he could use some ap ratio buffs, so getting void/liandrys feels better on him.
Increase the Q to 0.7,buff the ult to 0.4 instead of 0.3 and buff the special delivery to 0.4/sec to match the ratio on the basic W. It's kinda absurd that the basic W scales twices as good as the special delivery.
Aditionally, the ult cd should get lowerd to 1.75 sec and his base as could use a small buff, same for the ad/level.
Lower cd on his E would also help alot.