I think morality that is focused on reducing pain is the best morality.
This is because pain is the worst thing in the world.
If I had a choice between:
1. Living for 100 years, but burn alive every day
2. Not live at all, die instantly
I would never choose option 1.
So we see that life is not worth living if person lives in unbearable pain every day.
So the morality system should mainly be focused on value of reducing pain, or not increasing pain.
Pain even outweighs happiness.
Lack of great pain is prefered over lack of great happiness.
This is meassured usually by the "desire to remove current state of things".
People who lack great happiness dont rush to remove that and achieve great happiness.
But people in great pain rush to remove great pain.