I also have some experience in wireless power transfer systems. I have found out that inductive and capacitive power transfer systems are the only available designs to solve the issue. Both of them have very poor operating distances and a very dramatic rise in the losses when the distance between the source and receiver is growing. The edge effects cause a large leakage of the magnetic/electric fields and actually explain enormous losses when large air gaps are used. From my point of view, there are the following ways to develop wireless power transfer:
1) Invent (and make it useable) some new technology other than capacitive or inductive couplings;
2) Refine the design of existing capacitive or inductive systems to reduce the edge effects and to increase the power transfer distance