Why no AP assassin/fighter compensation buffs?

How come due to the changes to masteries and loss of runes a bunch of Attack Damage assassins and fighters received buffs (albeit and admittedly minuscule) but no Ability Power fighters/assassins did. Kha'zix (amongst others that others would probably feel better off without cough lee sin, yas cough) has received (a) damage buff(s), however, just as much as him, champs like fizz, ekko, and katarina (and other AP melees) relied on magic penetration/damage runes and thunderlord's to help their damage.

This is a recurring theme where AP assassins/fighters (melee) are constantly left out of beneficial balancing changes.

And while I'm on the topic, how come there is no AP "melee only" item yet?