On-blade control is the ideal, the old Kaman system was mechanically complex, but new technologies make it possible to do without linkages.
It is possible to do away with the swashplate and servos if the concept comes to fruition!
Dave, here is some undeserved salt in your wounds, I can across it this morning. Dr. Gordon Leishman on coax vs tandem vs single rotor:
http://www.enae.umd.edu/AGRC/Aero/merits.html