I don't think I've ever owned an AVR that didn't identify the type of signal it was receiving, AND the number of channels.

I think for televisions, you're going to be hard pressed to find any that support DTS passthrough. Only if they've bought a DTS license, and there's little reason for a TV maker to want to do that. Otherwise, most modern sets should support PCM and Dolby Digital, while older ones likely only support PCM.

I suppose beyond that, the question is... what is expected use for this piece of equipment that an AVR can't fill?