This is because of the simplified construction worker modeling due to the lack of adequate hardware power. When we get the next generation of CPUs i'm sure we'll be able to see some little people cutting down those trees, making planks and pillars from them and using them to build those houses as we fly over. Then they will not magically appear out of thin air anymore.
Sorry, the image just flashed through my mind and i couldn't resist
In all seriousness though, there's no use debating this unless we know the specs of that PC and the settings used. It looked fine in this week's tiger moth video, also judging by a couple of frame jumps it seems it's the real deal and not a render through the ingame "export to avi with no frame loss" tool.