Planned cities were often square, organic cities were often star-shaped. It doesn't depend a lot on the age or civilisation (though some civs tend to plan more, and others tend to have a more organic structure).
I do think that star-shaped layouts would fit better with 0 A.D., just because the territories are more or less a circle around the base. So starting the first circular territory with civil buildings, and the subsequent with more millitary buildings, you'll automatically get some sort of star-shaped layout. So it's a good evolution.
However, I do think about one modification. Normally, in star-shaped layouts, the buildings face the road or path leading to the centre, they don't face the centre directly (apart from the buildings in the inner circle around the centre). So if you know where your virtual roads are, you could rotate the buildings to that side.
And a major problem with star-shaped layouts is that you always have those pointy buildings at the end. They're impossible to simulate in 0 A.D. But I guess the result would look good enough even without those pointy buildings.