How well a mix translates is paramount. I can only imagine how much work must go into high end cinema sound production.
Absolutely, it's all about translation (!), almost anyone with enough time can create a mix which sounds good in the room in which it was created, getting it to sound good on a range of consumer playback environments is far more tricky. Incidentally, there really aren't any translation issues in high-end cinema sound! This is because cinemas are constructed and calibrated to a specification and the rooms used to mix theatrical sound are constructed and calibrated to exactly the same specification. So in theory at least, there is no translation per se. The translation issue only rears it's ugly head when mixing for cinema in a music studio or mix room designed for some other purpose, say a TV mix room for example. There's also often a problem with low and most mid tier film festivals, where they have to jerry-rig the sound systems and take them out of calibration in order to playback the formats and mixes of amateur filmmakers. Many/most film festivals are therefore a bit of a lottery as regards translation.
Specifically in one case, the similarities of the importance of perceived loudness in the midrange, vs the top and bottom end of the audible spectrum. ... Just like our ears, our eyes are more sensitive to the midrange than we might be aware of.
Again, absolutely! Anyone with any decent amount of professional experience mixing for TV would know intimately the importance of the mid-freqs. Coming back to cinema, the actual type/construction of the speakers employed in cinema sound systems are quite different to those used in consumer and pro audio systems and they have a different response, particularly in those all important mid-freqs. This is one of the reasons why there is effectively no accurate/predictable method of translation between the cinema and any type of mix room other than a purpose built theatrical mix room.
Sadly, unless we're looking at Death Magnetic levels of fail, the majority of audiences really don't seem to care.
Unfortunately this isn't true of sound. Audiences generally don't seem to care (or consciously notice) good, very good or often even excellent sound. However, poor sound or even just slightly below par sound causes howls of protest. The BBC's recent "MumbleGate" debacle is a good example, plus the fact that sound quality is consistently at or very near the top in numbers of complaints received.
I mean I play other movies on my computers, that have a more middle contrast, so if the colorist is suppose to make it so that it looks good on the average monitors, then it should look good on ours', when other movies do, right?
Not necessarily, how do you know you are comparing like with like? DCP for example uses a different color-space to TV, so you could be comparing a DCP grade with say a BluRay movie which may have been re-graded for consumer use. Although, from what you've posted on this matter, I very much doubt your colourist has graded or would know how to grade for DCP. I don't know that much about picture grading but this is certainly true with sound. If you actually got a cinema sound mix and played it back on your computer (or even a high quality consumer sound system) it wouldn't sound good! Watching a theatrical movie on TV (or DVD/bluray) you are not listening to the theatrical mix, you are listening to a mix specifically made for the format; TV or DVD/Bluray!
Furthermore, you would also have to define "good". Maybe these other movies look OK on your computer but if you were to compare how they look on your computer with how they are supposed to look (on the big screen), maybe they're not so good after all? Again, this is often the case with sound, people will happily watch a film on their TV or computer without ever realising the huge percentage of detail they are missing, which would dramatically change the "feel" of the film.
G