There certainly has been a lot of debate over the toning shoes. The companies marketing them resorted to the common snake oil promotional tactics making claims for the products that were not supported by the scientific evidence. This has landed some of the companies in legal hot water and some ridicule. A lot of the evidence that has been published on if these toning shoes really do give a tone-up or not has mostly shown that they do not which is why they got into trouble!
The way the shoes are supposed to work is that they are made unstable with rockers which are claimed to make the muscles work harder, which is what the evidence says does not happen. However, these shoes also realign the posture which has not been researched very much at all. This will have some positive effects for some people and maybe not so positive for other people. This means that the toning shoes may be worth it for some people, so do not write them off yet.