Sheen mechanic change idea

How would it be if sheen's proc would alternate between amplifying abilities and auto's? Obviously not the same numbers. Since sheen is very heavily geared for AA+ability weavers.

Make it so the the spell sheen proc and AA sheen proc can't be buffered together, so the champs with on hit abilities wont become the instant strongest abusers (like ez would be the most well known example of an item abuser). Also make it so the proc will still have a timer to use still. Similar to how the AA proc is % damage based, the spell proc can increase the spell damage by a % value. Trinity force can keep it's flat scaling on both portions; lich bane can have its proc damage modified so that the % scaling can be further increased by AP instead of the flat increase from AP, IBG can have a more utility based scaling for the spell proc like maybe a heal or shield for a % of the proc and have that scaling value increased by armor.