[onesolo]

OK, sorry you lost me a bit. So in other words, sound from a DTS HD player with passthroug enabled is far superior than Kodi Multichannel PCM.
The Amp creates virtual speakers and has better sound image, with Multichannel PCM it does not do that. Never thought of that.

only with DTS-HD MA 7.1 from my test. it's not big difference ,but with my HT i can hear.

Is it impossible for Kodi on the RPi 2 to have passthrough DTS HD, or is it something that could happen in the near future?

no

I still don't get it... it only has to passthrough !!! passthrough, the word says it all... they don't have to deal with it...