theory to optimize the long term

Good GGG, thinking, I realized that the best way to ensure that the bosses are not farmed indiscriminately and lower the price of the IG items so much, I came to the conclusion that I had to add a unique modifier to the bosses in which every time the character kills the boss of the instance, he adds 1% of defensive statistics.
Thank you very much in advance for your attention and greetings to all.