Change Devourer to work like this:
On-Purchase: 50% AS, +30 Magic On-Hit +1 damage/stack up to 30 stacks transforms to Sated Devourer
Sated Devourer: 50% AS, +60 Magic On-Hit Also on-hit, enemies get a stack of Chewing, stacking up to 5 times lasting 3 seconds. Each stack of Chewing increases all of your damage to that target by 2%.
This lets you quickly ramp up your damage, but it stops the stupid abuse cases for the double-on-hit procs.
Posui Gart1 votesImagine if you are playing a jungler. Would you build this Devourer? It adds 10% of your damage, and requires time to be stacked.
Nebuul1 votesIt gives 50% attack speed, 60 magic damage on-hit, and increases your damage to a target by up to 10%. It is stupid strong. The only reason something like this can even be considered in the game is because sated devourer is so stupidly powerful that it makes everything else look weak by comparison.
Posui Gart1 votesEhm... no? You need 20 minutes of stacking for 10% damage? Meanwhile a usual ganking jungler with Warrior will win every lane for his team. So you are coming out of jungle to see your t1 and t2 towers down and you are saying something like "Hey, don't worry, I have +10% damage after my 5th hit that I will not be able to do because I am super squishy, and I didn't build any tanky items because I need more damage so this +10% really matters" and after that your team surrenders Devourer needs some nerfs, but your idea just kills the item. Maybe +25% damage after FIRST hit would work