In dota almost all auto attack related items are more effective on melee auto attacks

That's because they have a stun or bash built into a melee, and have a gap closer to close the distance between them. Also many items to enhance the attack speed, and armor in the game to fucking slaughter ranged champions.

Another thing, that wouldn't fix ADC, you gotta tweak the support items first.

If anything you would be tweaking static shiv. The biggest offender for the marksman.

Though I haven't played Dota 2 in a long time.

add turn rate PLS