This is looking cool but you should make a nice render to see the exact progress.
Also i think you should work a little with the stairs since i think that after so many years the stairs wouldn't be in the same place as the were at the begining.
And the collumns could be a little more broke and cranked in some places.
As farinasso said make the edges of the shadows little more smooth, try it may be looks better. And if use dark black clouds or blue sky then what you say?