I think you can significantly speed up the pouring, if you can increase the arc approximation/maximum deviation. Also, if you have multiple pours on the same layer with the same net, merge them.
I havens worked with so complex PCB design yet, but few minutes was possible with 4-6 layers and few dozen polygons. I would shelve a bunch of those inner layer polygons and only touch them at the end. Also, I use some mechanical layers to set up poligon boundaries, just a technique I've found useful.