The problem is Aphelios's passive.
Aphelios gets too many free stats from his passive. They cause him to scale too hard and too fast, and he doesn't need to sacrifice anything for them.
He doesn't have the highest Base AD or Attack speed, but in combination with his passive, there are few marksmen that surpass him without any modified basic attack mechanics or reduced damage.
By level 18 he is guaranteed +24 AD, +36% Attack Speed, AND +18% without any items, runes, or other buffs.
I think the "AND" is really the issue here.
Change his passive so they scale slightly lower and he can invest into each up to 9 times (yes, I know he only has 18 levels)
This means he has 3 options
- Maximize 2 of the 3 stats and get 0 benefit of the 3rd
- Maximize 1 of the 3 stats and get partial benefit of the other 2
- Maximize 0 of the 3 but get partial benefit from all 3
Instead of Attack Damage 4 / 8 / 12 / 16 / 20 / 24 Attack Speed 6 / 12 / 18 / 24 / 30 / 36% Bonus Armor Penetration 3 / 6 / 9 / 12 / 15 / 18%
He gets Attack Damage 3 / 6 / 9 / 12 / 16 / 18 / 21 / 24 / 27 Attack Speed 5 / 10 / 15 / 20 / 25 / 30 / 35 / 40 / 45% Bonus Armor Penetration 2.5 / 5 / 7.5 / 10 / 12.5 / 15 / 17.5 / 20 / 22.5