Users do not want, and should not be asked, to become xorg.conf and nVidia News Forum experts. Many things have been discussed before - but even I get confused by all the nVidia developments and options. And I am a developer. So in short you expect too much of users.
As a developer, you should be aware that there are highly functional, user friendly installer scripts that support Debian. The problems you are talking about have been dealt with, and are basically solved. Our users do not have to learn the ins and outs of xorg.conf or nvidia driver install unless they really want to. In fact, they do not even need to learn how to run the graphics installer script at all, unless, again, they really want to.
So users who want to do it manually can, and users who don't just run the scripts, which take care of all it for them.
I have as of yet heard exactly zero complaints from users about switching to dynamictwinview default of on. As soon as I hear one I'll let you know, but that one is going to be far less than 1% of the total, less than 0.01% of total in fact. Actually, I can't remember any complaints about nvidia driver install at all. So I'd say, good job to the nvidia team, they keep up with latest kernels, apply fixes in a timely manner, and their stuff seems to basically work. And they make my life a lot easier than those bumbling boobs over at ATI, that's for certain. Sure it would be nice if nvidia driver was open sourced, but that's another question for other contexts.
The only complaint I've heard was the one that made us change the default to dynamictwinview on recently, previously it had just been an option.
Since we have many average users, I would imagine that if the issue raised here were actually important and annoying, I'd be hearing about this all the time. Sure we do now and then hear the question: why does my monitor report 50 hz when it's actually y hz, but the answer does not cause them distress or problems, nor apparently does it damage their emotional well being.
Sadly, one thing that seems to not be working nearly as reliably, is the debian set of nvidia driver debs, those are unfortunately not nearly as problem free, up to date, or reliable, as running the nvidia stuff directly, via scripting to handle all the cleanup, tweaks and configs you so correctly note that most users have no interest in having to learn.