Not Seeing any proper DPS high AP building melees.
All I am seeing is assassins, burst "tanks", and typically AD/mixed damage building fighters that troll build only AP. Be cool if they added a high scaling Yasuo style champion of the full AP favoring variety, heck could be neat if this champion would toe to toe Yasuo throughout the game as an equal. Just making sure this one doesn't make half of league wanna bang their head on the desk.
Spare of the moment day dreaming...
Would be very unique to have a champion that scales well with Crit and AP in a passive and/or their abilities. It could be a modified effect on this champion where the crit value adds bonus magic dmg to the auto attacks based on a combination of the amount of crit and the amount of AP(requiring both to have any) instead of it traditional doubleing of AD dmg randomly. The scaling dmg abilities could utilize the amount of crit the champion has to increase the abilities damage based on the percent crit chance up to 100% more.
This in order to promote unique builds such as this:

This champion could be THE swordsman of the shuriman desert in modern Runteria following the brooding lone wanderer trope or somthing of the like.