Thank you for your feedback. I have a Denon AVR-X3300W.
Compared to a movie, when I watch a TV drama with a 5.1 soundtrack, I rarely have problems understanding the spoken word.
In the music industry, most producers will review their work on various sized speakers and at different volume levels before they release it.
I get the impression that when movie studios create a Blu Ray or DVD, most of them take care in encoding the video for playback on a TV, but just copy across the multi channel audio without consideration of how it will sound in the home.