horlick97-
Your comment about the propulsive efficiency of the X3 configuration in forward flight is correct. But your point about potential problems posed by the propellers is not. EC has filed some
patents describing a wing/propeller configuration that will resolve the situation. The X3 demonstrator used that particular wing/propeller configuration because it could be readily adapted to the existing EC155 airframe.
Regarding the article John Eacott linked about Airbus Helo supposedly cutting back on "big innovation", I think that notion is wrong. What the company is doing is focusing their development efforts on things that will provide commercial value. The problem with concepts like Sikorsky's X2 or AH's X3 for most commercial applications is whether the higher speed capability justifies the added cost. There are a couple core technologies that need more development before these high-speed compound helos become commercially viable. The rotor blades require better aerodynamics and structures. Reliable high performance blade control systems (like IBC) are needed. Variable speed turboshaft engines are also essential, since they would allow varying the rotor speed without the added weight and complexity of a multi-speed gearbox. It is a better use of resources to develop these things rather than on nonsense like electric hybrid propulsion systems that will provide no value to their commercial products.