I can't really give you a solid answer on if the pond is a 'good start' if it's truly is a retention pond for construction. As you may be aware, most any kind of retention pond is designed to accumulate, and then drain off, any water from run-off. So right from the start, it goes against what you would be looking for in an actual pond for recreation. I think the short answer is that it may not be a good start towards getting the pond that you want.
Many times, once a pond, for any purpose, is dug and filled, it makes things more difficult to do any remedial work that could be required to make things 'water-tight.', no pun intended!
Now, sometimes, excavations are made to create a base or pad for the construction of a structure. That could also be what this 'pond' is all about, but in that case, did the builder do the necessary steps to make it a permanent pond, or was the idea to put some kind of fill back in??
Makes complete sense.
The lots do not look like anything but lot leveling has been done. That's to say, I don't believe they've done any excavating to build up any of these properties, but that's just my observation so I'll make sure with the builder.