I'd like to second the general tone of this thread, and I hope I (we) don't sound stuck in the past.
A well-known author who has published several "handbooks" for recording, mixing and mastering engineers has a habit of posting on his blog isolated tracks from old hit recordings, for example, the drum and bass track of The Beatles' "Hello Goodbye." With the rest of the mix stripped away, he always finds some little musical or technical anomaly, and goes on to say something like "...if this had happened today, we would have fixed it."*
The idea that you could "fix" something that was good enough for George Martin, Paul, and Ringo at the time, on a record that millions of people
still love 50 years later, just seems wrong to me. I mean, doesn't the word "fix" kind of include the notion of "improve?" I think the musicians and technicians working at Abbey Road in those days must have understood that concept, too.
Even with all the tools I now have at my disposal to fix stuff, I believe that music should be organic, and as such a little hair growing off the side of it is acceptable, if not downright desirable.
*To be fair, after I repeatedly challenged this author he finally admitted that he doesn't mean it should be fixed, just that it would be fixed. Considering that there are a lot of budding engineers reading his books, I think he should make that disclaimer on every one of his "isolated tracks" posts.