Since live, the songs are stripped from the sound that people like. It's hard to argue that the preferred (original studio) version is an overproduced one. Overproduced clearly has a negative ring to it. IMO at least. I mean, "over" isn't in the word for nothing.
I found
this, to make my view on the term more clear:
the idea that a record producer or mastering engineer has made "unnecessary" additions or changes to a record in the production process, and in doing so has decreased the quality or enjoyability of the music.
Going by your definition above,
Forostar, I'd say that most
fans (positive) of the studio SiT are not going to define it as
overproduced; since, it could be argued, the quality & enjoyabilty have not been decreased by that mix (--as defined by your quote). However, it's clearly been
produced to within an inch of it's life; Maiden have never (really) replicated the sound of SiT live. Hence, as most people speculate, why they play so little of it live.
One could be more critical though. If you don't like the idea that Maiden made an album (like SiT) and
can't replicate the sound of it live (if you accept this argument), then maybe the term
overproduced is apt. Maybe, to you, that very fact (can't replicate live) decreases your enjoyment of the album; and perhaps you view that quality as a kind of fake "studio" quality, because the musicians themselves did not produce that sound.
Still, I have no idea if you,
Foro, think it's overproduced (by your own definition) or not.