Peter the developers have done an excellent job maintaining demand by squeezing supply and offering incentives. Many people really enjoy the newly built homes and regardless of the market conditions, will continue to buy in these new subdivisions.
I would absolutely wait for a resale in the development if you can. I would absolutely wait for anything anywhere if you can. If your down is going to be 100% based on the proceeds from your sale then I would sell now, then rent, then buy later if at all possible. That way the nut you make on your sale will be safe and locked in, just don’t fritter it away anywhere.
The developers will always be able to offer better deals then resale property regardless of the market conditions because of the margins they make.