Layering should have no impact on queues because it does not impact maximum server capacity. It should only impact how many people with whom you can interact in one zone.
And no. You are confusing sharding and layering. Layering makes copies of the world so a realm rhat could normallu have a cap of 3k now has 3k per layer.
Sharding is what splits up the population per zone
True but how would you? At the start, a “medium” realm with a slew of layers had more than the highest vanilla server. HOWEVER, as they remove layers, you may not notice a change in overall server population. At least when viewing the “fullness” indicators in the server chooser. When they remove a layer, that indicator may jump up a notch, making it appear more full than it had previously. When in reality, it has less total population, but less layers and a lower cap.
HOPEFULLY, all servers will be “full” status when layers are completely gone.