If I had to choose one word, I would say "tighter". So I guess "clear up" is closer in your wording, and not soundstage expansion (hey at least we didn't say velvety or chocolatey or faster). Ok, so acoustic treatments did nothing for you either- in my case, treatments did do something for me, I liked what they did quite a bit, and this was before Audyssey. When I finally ran MultEQ XT, the jump was about as big as the treatments themselves (but already installed at this point). That says a lot to me. I'm talking double digit panels weighing hundreds of lbs in total. The MultEQ XT is basically free, depending on how you look at it.
So, I can't remember the exact reason why, but there was a little while there where I disabled XT. Maybe it was during my sub build. Anyways, I have a friend that loves the blues and classic rock, and brings over concert BDs to watch, whether it's Jimi, the Rolling Stones, Last Waltz, etc. Well, he brought the movie The Doors over, and while not exactly a concert disc, there is a lot of music. He was downright disappointed with the SQ. I then told him my XT was disabled, and that could very well be the reason, as he was used to the SQ with XT engaged (he loves the SQ in my HT, and hence he chooses to watch the concerts at my place). He asked, Really, that tech makes that much of a difference? I replied that of course I cannot be absolutely certain, and in fact some people dislike this tech, but yes IMO it is very likely the reason that you think this title sucks . . .
I don't know, but I have a question for you, does the $20,000 McIntosh even have bass mgmt?
DTSMA does not have any more soundstage than mch PCM or TrueHD. MA and T-HD are simply compression algorithms for lossless mch audio. That said, mch lossless is good stuff!
The wides vs heights, etc, is more dependent on the spacing and room itself, as far as if it's even worth giving it a shot. Heights are used more often, if only because people usually don't have very wide rooms (especially when lengthwise setup is the best for acoustics).
Why does it have to be in the BDP? Do you happen to use cable, and if so, would you consider a Tivo?