From my experience there is a vast difference in the amount of effort that is required to smooth out wax sculptures versus sculptures sculpted with any of the polymer clays. The underlying principles and concepts are the same but wax, when cooled, is a much harder medium and thus requires quite a bit more work to achieve the desired result. Keep in mind that this is under the assumption that you smooth out your polymer clay sculptures prior to baking, which I have always done in the past. Some sculptors will bake their polymer clay sculptures and use wet sanding techniques for the final smoothing stages (this process will exponentially increases the amount of work needed to smooth out the sculpture).
Recently I had put together a little article that outlines some of the key differences between sculpting with wax and polymer clays (http://www.polymerclayfan.com/sculpting-with-wax-vs-polymer-clay.htm). In hindsight, the review was more of a comparison between sculpting with Super Sculpey and a relatively new wax called FUSE. I think it is important to point out that not all polymer clays are created equal and the same case could be made for wax. As of the writing of this article, FUSE is the only wax I have ever tried so the chances are that my opinions regarding sculpting with wax could drastically change from one wax product to another.