As they already said, 8 men and 24 men couldn't go in the same roulette, and the 24 men ones with 2 tanks, 2 healers, 4 DPS can't go in the same roulette than the 1 tank, 2 healers, 5 DPS. So it seems unlikely they will create one.

I think the earlier 24 men raids should have level sync or ilvl sync, since overgeared people ignoring mechanics make them no fun to do.

The roulette would need some reward. Since you can get an esoteric upgrade item just for Void Ark weekly (and only one), it seems unlikely developers will make possible get more of them. Other rewards wouldn't be attractive I think.

Let's see what the relic quest brings, it might well be we will have to revisit the 24 men raids and not only some of the old dungeons?