Problem: absolute ability scores don’t actually matter that much. But the perception of balance between players does.
Idea for Solution: an ability score draft. Players can draft 2 of their ability scores (the rest will be random…3d6 straight down). Have the players decide amongst themselves the order of the draft (or pick it randomly). Use Catan drafting rules: the first player gets the first and last pick, the last player gets the middle 2 picks. Roll 6 (or 8 for a slightly higher power level) ability scores per player in the group, using 3d6. Write these down. Then players draft 2 scores from this set. The rest are discarded.