Why wouldn’t you use the stereo mix on a stereo setup regardless of whether or not downmixed 5.1 is kosher? Is there some advantage to downmixing a surround mix?
If all I had was a stereo setup then I would most definitely use the 2.0 track as I did before when one was available on a DVD/BD.
In my situation though, it looks like I’m going to be stuck with a 3.1 (L,C,R,LFE) for the foreseeable future. I’d like to have that LFE channel if possible, I’m less concerned about the center channel, but I was curious where the latest versions of the restored 5.1 tracks stand in regards to downmixing. It was mentioned early on that this was not a good idea with these upmixed tracks, which makes perfect sense, but I believe they have been updated since that remark was made so I was curious if anything had changed in this regard.
As far as I’m aware, the only benefit to downmixing 5.1 or 7.1 comes from not having a 2.0 track available on your BD/DVD, and all you have is a stereo setup. Otherwise you’d be missing audio, obviously. 😃