In terms of aesthetics, I'm probably with Jalyha in preferring the first one, but it's a pretty close thing. That opinion encompasses both buildings and the main road (and I think I recognise that cobblestone texture).
Also, I'm not sure the dark yellow/green lanes are working at this stage; perhaps a browner/redder/paler method would look better?
Also, if you want to make it look more crowded (as Scoopz notes) I think you should not only add buildings to the outskirts, but start squeezing more into the inner parts. You're mapping a city over time, which is a cool idea, but that means you have to accept that no city remains unchanged. Cities grow, but they also change internally, just about every generation (the only parts that tend to remain unchanged are the streets). It goes back to the thing I said earlier about the burgage cycle (and as Jalyha points out, people also upgrading their homes). I think it would be good if you started making the existing parts of the city more crowded, but if you have an in-world explanation, than, like last time, stick with that.
I prefer the first one too, for aesthetics, as well, and mainly for the roads. Roads are way too dark on the second imo.
The type of roof people are going to have really depends on the climate and culture. Assuming it's Mediterranean or arid in nature I'd think the more crowded the city the more likely it would have flat roofs for extra personal space. If one owns a house in that area and they had sloped roofs they'd probably also have the ceramic tiles. You aren't going to spend all that money in a property and then roof it over with a bunch of garbage. Once a city is too crowded most of the dwellings will have roofs for privacy.
In the city you have there I'd guess at around a third to a half would have tiled roofs.
Personally I like the second better because the colours are more consistent. Any stone buildings (for regular folk) will obviously bear the same colour characteristics of the surrounding terrain, as that is their building material. They will also use the same rock for the road meaning the houses would be the same colour as it. In other words I think the first one would look just as good as the second if the road were a more lightish brown like the houses, and if the ground had more tonal relation to the houses.
That makes a lot of sense Falconius, but if I make buildings and roads the same color it become difficult to distinguish them and less aesthetically pleasing. Also, isn't that possible that they used bricks for buildings and stone to pave their roads? That's what the Romans did, mostly, for example.
Maybe I could split the difference by using these different roofs colors (in order of affluence): hay, tiled wood, flat brick (the brownish one), flat stone (the grey one), stone+ceramic tiles, ivory/white (paint, or even marble)+ceramic tiles.
For the road I could use either texture, or perhaps the cobblestone one but in a lighter hue (although dark streets have a certain allure too).
I personally prefer the darker roads. To me the lighter ones contrast too much with the rest of the buildings - most notably with the wall. The darker roads match the wall quite nicely and allow the building layout to take more prominence. A tone somewhere in between the two might give the best of both worlds though, might be worth a try. The new roofs don't quite fit the rest of the map yet imo - I think they might blend better if they were made slightly less bright (the grey roofs much more so than the others, which are almost spot on).
However there's a fair chance that the colours would match much more on a different monitor, so if it looks right to you then ignore the above.
I like the style in general, looks really nice. I wonder if there's a way to make the cobbles/paving stones follow the direction of the road... it'd be possible using a direction controlled brush and a clipping mask in photoshop, but it might be a bit too much effort to be worth it. Something else that could be nice and would be a bit more simple is adding a very slight emboss to them to give the roads a little depth (assuming they're slightly raised in the middle as many roads used to be).
I love the concept of growing a city this way, looking forward to seeing how it develops!