I do believe the future will be a higher efficiency design but I don't believe it has arrived quite yet, at least not for the masses. Class D or switching amps do a lot of things right and would not hesitate trying some for surrounds and maybe center but not mains.
The December issue of Stereophile reviewed a $50,000 and a $6,000 set of monoblocks by highly regarded companies - they know how to do sound. Now so many people say Stereophile and others just bow to the advertisers and give glowing reviews but they failed to recommend either. I also see where people jump on the class D bandwagon but after a while of living with it many switch back to class A/ B. I also believe this won't show in a blind ABX audition, you need to live with it. However, I will admit all my knowledge on this is second hand.
Perhaps NAD or Devialet or someone else will prove me wrong, I would like less heat in my media room.
Main Kef: Reference 205/2 & 202/2c, Surrounds: Kef XQ40, Velodyne Optimum 12, Integra DHC 80.3, Ayre K-5xeMP, Oppo BDP-103, Bryston 4Bsst2, Parasound Halo A31. Second B&W: 685 (3), CCM618, Def Tech Powerfield 1500, Onkyo TX-NR1008, Zone 2 Klipsch AW650.