The great arena of Greyhawk city

[torstan]

That helps a lot. I'd still reduce the shadow from the stands on to the sand a little. Also, an overall gradient from light to dark on the stands would be helpful, with light at the top and dark at the bottom.

For the nobles I'd suggest some sort of coloured awning - they will certainly want to be sheltered from the sun. For merchants and other good seats I'd suggest cushion. The plebs can sit on rock. That should help to delineate different economic categories.

[Ascension]

I second the awning and cushions. I'd also set up some sort of colored bunting to act like a velvet rope and if you can make their area sort of elevated. Last thing is, what is the material it is constructed from? It looks sort of like fresh concrete so I'd lighten it up. Really cool though so keep up the good work.