Trophy System (game rework idea)

I love playing the game, its addictive. But I wanted to come up with an idea that would make the game become impossible to step away from. What if the game had a trophy system?
No I DO NOT mean like PlayStation or Xbox. I mean victory trophies from gods you've defeated. Battle trophies with in game benefits.

I'll give an example using my favorite god.
Mercury had a sword in ancient mythology that he used to kill Argus. Killing Mercury in game five times grants you a trophy; Sword of Mercury. When playing as the same character you beat Mercury with, the sword is then buyable in game.
This appears in the shop:
Sword of Mercury (1800)
+50 physical penetration
Every physical attack on an enemy god increases your attack speed by 5%. Maximum 20% for five seconds.

Every character is given a unique unlockable item. Some are weapons and armor; others are actives or consumables.
The game keeps track of how many times you have defeated a certain god and with which character.

I like the base concept, although these items have to be incredibly balanced for this to work.

Most would have a unique effect that isn't strong enough to be a game changer, the really effective ones would be priced high to make them end game items. Each one would be given an effect that matches the character it is a trophy of.

I love that idea but i think it would be really hard work to make an item for every god in the game and make the efects different for every god so they arent the same and research what item it should be because aphrodite with a giant stick like herc has or a cupid with Tyr´s sword.