This system is an improvement over not having it. It makes you think somewhat about your items and your overall build.
You build your char around onhit effects so you go ancestral etc. Seems fair to me.
My only issue is if it becomes too easy to get enough of all 3 so you dont care about them anymore.
Maybe have different tier rolls. So the higher the roll of “Crushing Blows” the more ancestral you need to be able to use it. So if you have a char that focuses on demonic, but have just a little bit of ancestral you can still get an item with a low roll of crushing blows and able to benefit from it.