I would agree that manufacturers have been having problems building reliable HDMI pre-pro/receivers of any sort with 1.4/1.4a perhaps being the most difficult (hence devices like the HDS-12). At this point there are a number of designs out there with HDMI 1.3 including room correction including the Sherwood R-972 (which has pre-outs).

FWIW, I don't think that room correction with the exception of Trinnov has been all that difficult as many manufacturers have released room correction using Audysssey based chipsets as well as room correction from others.