Are you sure that's a single sole? It looks like a double sole to me from your pictures. It certainly look thicker than the typical single sole. It does appear that they changed the heel so it's no longer a combination heel. I personally prefer combination heels because it looks nicer, but functionally I don't think there's any difference.
Positive. I'm comparing it to one of my normal single-sole pairs and it's about the same. On my other double-soles, you can see two seams, one between the double soles and one between the top sole layer and the welt - here there's only one seam between the sole and the welt: