All 3 attributes heroes gain attack damage from strength. ( draw a bow also need strength, however.) ( wield hand/staff harder should make the launched object impact more powerful.)( steadier hands, more powerful bullet.)

Strength heroes gain double attack damage from strength.

Agility heroes gain double attack speed from agility.

Intelligence heroes gain physical attack damage from strength and gain magical attack damage from intelligence. ( like Javelin proc, Mind Breaker.)

Reduce all heroes' strength gain a little.
Add some exception.