The Game was a strange choice of album for a multi channel mix. I'm sure it was done for commercial reasons because it was Queen's most successful album in the US. But the ethos of The Game recordings was a stripped back simpler sound compared to earlier years. One quote I heard was "why use two notes if one will do". So to me that means this should have stayed as stereo. Remix for mono perhaps?
A Night At The Opera was clearly a great choice for a multi channel mix. But instead of The Game they should in my view either have followed it with A Day At The Races (which is a companion piece to Opera really), or better still every fan of Queen's early years would dream of a multi channel mix of Queen II.
As for why mixes were changed to go to more 4.1, that's because as Brian May gained experience with multi channel mixes he realised the Centre channel is bad for music since it messes with the imaging. I'm surprised there's much left on the .1 channel, but since I don't have a sub I wouldn't notice if there was nothing.
Don't buy the HFPA blu ray of A Night At The Opera for multi channel, the mix has been ruined by loudness wars compression. It's the same ruined multi channel mix as the 30th anniversary DVD-V (DTS and DD multi channel). The only benefit of those disc for multi channel is God Save The Queen is a proper discreet mix, when they did the DVD-A they couldn't find the multi tracks (because they were stored with Queen II era stuff from when they started using it to close concerts) so the DVD-A has an upmix of God Save The Queen.
One thing that is good about the HFPA blu ray of Opera is the 24/96 LPCM transfer of the original stereo master tape. I sounds fantastic to me, cleanest stereo version I ever heard. I finally know what tape saturation sounds like, I can hear it in this transfer. It sounds like a completely flat transfer to me, and makes the blu ray worth the price.