If you think this suggestion would be against the newbies, then you maybe misunderstood. The goal of the suggestion is exactly the opposite: to attract more. Please read the details, it is important.
First I would be glad to citate the Area51 FAQ:
"The questions on your site say a lot about the community. To attract experts, you need a site where people are asking very interesting and challenging questions, not the basic questions found on every other Q&A site. Your goal is to make it clear that this is a professional site. "
"Remember, pro sites WILL attract the enthusiasts, but not the other way around!"
Most of the questions request for help in some awk/sed/sh scripting or some similarly trivial task for a power user. Answering them is an easy way to collect reputation, but doesn't attract highly qualified visitors. For example, a developer of kernel drivers won't be here too long, because the topics which are interesting here for him, would be closed or migrated to the StackOverflow.
But the StackOverflow is a very broad mix of very different topics, asking highly specific things isn't really feasible there.
In my opinion, what should be allowed:
- Programming questions about the standardized, unix-specific APIs. Especially about the posix standard.
- Programming questions with deeply unix-specific object (especially kernel / libc hacking).
- Programming questions about the internal workings of unix-specific software (some examples: kernels, apache module internals).
Of course it would result in some overlapping with the StackOVerflow. But I don't think that it would be harmful or problematic. The SO, being a very broad site, already has a lot of overlap with other SE sites (f.e. with Prog SE or Android).
The common (StackExchange-wide) consensus about the overlapping questions is that they remain, where they were opened (i.e. no migration, if it is ontopic on both sites).
In my opinion, if the Unix SE wants to attract the experts of an area, instead of being a help site where power users help not-so-power-users with configs and scripts, it should change to a behavior similar to the ProgSE - StackOverflow relation, and follow the more global, SE-wide consensus, instead of using a homebrewed, self-harming one.
Extension: On the comments it seems to me as if you, dear reader, would think, I am argumenting against the enthusiast-level content. This is completely a misunderstanding, my argument is exactly the opposite: read my citation of the area51 faq. Having also high-level (i.e. programming) questions will attract more enthusiasts, and this is also a goal.