This might seem like a hot take, but at the end of the day, it's Roulettes.... It really doesn't matter... You could have 4 DNCs that all dance partner the healer and use devilment and technical at the exact same times, and it really just doesn't matter... If the content were anything difficult, I'd agree, but it's just roulettes... Changing the system to something like what is suggested in the OP would do nothing but extend queue times for DPS queues substantially while reducing the total content time by maybe 2%...