Do ducted fans have a future in forward flight aircraft? Can they be made more efficient than open rotors?
Fan shrouds are a fix for a problem that can normally be designed around in other, more efficient ways. They do reduce tip loses, but usually the tip loses are smaller than the weight and drag penalty of the shroud.

The fundamentals of prop/fan/rotor design is that thrust is proportional to the increased momentum of the air flow, but the power required to get that thrust is proportional to the added kinetic energy i.e. the ''square'' of the speed increase. 

Therefore small, highly loaded fans will always be inefficient compared to a traditional helicopter rotor. The fact that they suffer from large tip losses only makes things worse.

So no, we won't see lots more ducts on future aircraft - except that jets already use ducts because the size of their fans are limited by ground clearance and keeping the fan blades subsonic.