You also chose tenacity as your example, which is the one stat that buffs pretty much everything, including damage. Like it was mentioned it you are racing an enrage timer that difference is clear or fail. Which is huge. esp if all 8 party members have the same issue of being off melded, and the more your rotation is off, the larger the impact of u being weaker is. If all 8 party members are missing 1.5-2%(not everyone has tenacity to help their dmg) of potential damage from melds alone that's 10%dmg your whole party is missing.