I have only watched part of insterstellar on bluray and I can hear dialog much better than the IMAX I saw it in. I am not sure what type of IMAX it was but the screen is taller than wide.
Interesting. For what it's worth, I did see a few complaints about not being able to hear the dialog posted to the official thread here. Putting aside the criticism about its clipping, this definitely seems to be a hit or miss mix with people. Maybe that is poor mixing in and of itself, since the mixer is supposed to make it sound good on a wide variety of systems. At the same time, I am intrigued that system/room performance makes such a difference with this one. I have noticed that about other recordings I have that I've had the chance to listen to as my system develops. Some things I own sound good no matter how my system is set up, but there are other things that sounded relatively poor in earlier iterations of my system that now sound wonderful to me. I imagine "Interstellar" to be in that category as something I would not have appreciated a year or two ago.