This I agree with "I'm guessing "over-producing" is when you make bad/average musicians sound really good by editing the shit out of their playing/performance.".
But since as was said, the OP was not really talking about that, I think the concept of "over production" is a crock of shit, seriously.
It's in the same fucking stupid league as the word "pure/purity".
I was talking with some guy on msn yesterday and I was talking about how I was starting to get a real interest in audio engineering/production and I said "Once you start learning about this stuff, you truly appreciate the sheer talent and hard work that goes into an amazing production". We were on the topic on Paramore as well, so I mentioned the album Riot! as being an example of really gorgeous production.
But his reply was "That's all bullshit, music should be fucking pure" and then all the crap about how it should be done live and all that total shit. He clearly had no idea what the fuck he was talking about.
What exactly is "pure"? Because I'd really like to fucking know, because as far as I'm concerned just like "over production" it's a bullshit term used by people who have no idea what the fuck they are talking about.
Let's take a live performance.
Is the music still "pure" by the time the guitar/bass cabinets and drums are mic'd up and the audience is hearing it all via the PA system/monitoring systems?
You know, maybe that just isn't pure enough.
It's only pure if you can only hear the backline by itself.
Oh no, wait, that's not fucking pure enough, the guitars are being amplified by electricity, the band should be playing unplugged so you get the "troo" tone of the wood and the fingers on the strings as they play.


uke:
See what I mean, it goes around in this big, stupid fucking circle.
I then explained to him what a load of bullshit the concept of "pure" is.
You walk into a studio with this concept of "pure" and try to argue with the producer/engineers that your approach of "pure" is correct and surprise surprise, the end result is gonna sound like garbage, purely (no pun intended) because you have no idea what the fuck you're talking about.
So basically, I get around this problem by not worrying about "over production" nor "pure/purity" and just going for what should be the proper end point, which is SOUND GOOD. Obviously someone like Andy Sneap has that approach, he wants his shit to sound good.
If it means quad tracking (which is hardly realistic in the sense of real world performances where you might only have one or 2 guitarists) to sound good, then so be it.
If It means having a guitarist punch in his shit again because he screwed up during his first performance during tracking, then so be it.
As long as it sounds good, why argue about trivial bullshit like "over production" or "purity"?.