Just like last time, we'd probably find out on the night of the finale. That was the only good part of that god-awful reunion show, when Jon made the announcement of Season 2.
I think this season will do well, especially for the fact they actually incorporated international destinations this time
...Yeah, I know, Family Edition had a route like this, but that season was very watered-down, and it tanked Amazing Race's ratings. Amazing Race Canada did a considerably better job of it. The tasks last season were not easy!