Summarizing and paraphrasing your questions:
Should this stack be welcoming to strangers?
We should be respectful to everyone, and to the degree that we're not enabling help vampires, we should be welcoming.
I have always maintained that we should be polite, but firm with help vampires and trolls.
Should we expand the site scope to include consumer networking devices, dns, etc...?
No. (but I mean that in the most welcoming and nicest possible way)
Summary Version
As I wrote this answer, it grew much longer than I hoped it would. To summarize a lot of stuff below: We don't want to bite off more than we can chew. If we open the topics up to billions of people, we make the site a thousand times harder to manage.
Details
Perhaps you'd like to understand why I don't want to expand the site's scope to what you suggested. YLearn's answer covered some of my reasoning, but I'll point more reasons for advocacy of a limited NESE site scope (at least to start, while we have a small number of active close voters).
First let's look at some numbers...
- Number of users on the internet in 2015: 3 Billion users
- Number of network engineers in the world: maybe 3,000,000 Note 1
- Number of NESE close-voters (assume beta requirements of 500 NESE points): about 100 users (as of May 2015)
Boiling it down, assuming 100 close voters...
- Ratio of total internet users to potential-NESE-close-voters: 30,000,000:1
- Ratio of total network engineers to potential-NESE-close-voters: 30,000:1
Some math behind community-building
Before NESE was proposed, I had been an active Stack Exchange user for a couple of years. While I participated, I noticed that moderation can make or break a site. During beta, our most basic mission is building a network engineering community, which is often considered a group of people with a common interest.
But in our case, building a community is more than merely people with a common interest, it's also about building a core group of users who we trust to moderate the site. Stack Exchange sites are not moderated by the people with diamonds, they are moderated by the entire community (explicitly the close voters). Like it or not, every time you upvote, you're incrementally empowering that person to govern the community, set the rules, vote for closure, etc...
So, back to the math...
- How many people could have DNS problems / questions? Billions
- How many people could have consumer-grade networking questions? Billions
- How many people are seriously interested in Cisco / Juniper / etc...? maybe 3,000,000
If we open the list of acceptable topics up to allow DNS or consumer devices, we make the site hundreds-if-not-thousands of times harder to moderate.
Rep Hounds
Furthermore, if we start encouraging "simple" questions on the site, we also have the reality that some percentage of those active users will be rep hounds, who answer anything and everything so they can get more fake internet points.
The more "simple" questions we allow on the site, the more we get of those people who typically resist keeping the site as purely professional network engineering. This winds up diluting our professional network engineer community for little gain.
Close voting on life support
Our NESE close-voting is already on life-support; while I think that's a common problem with other stack exchange sites, the point is that we should be smart about what problems we tackle while we have a relatively limited number of close voters. Remember it only takes one person to ask an off-topic or confusing question, and five people who care enough to both read and vote to close it. The numbers work strongly against the close-voters early in a site's life; especially if we open the topics up to (potentially) billions of people.
Taking the example of DNS... and setting aside my other arguments against DNS on NESE, one might argue that we don't have to make this an all DNS or no DNS site... sadly, I think it's really that black and white when we have so few close voters. It's a lot of work to suck enough details out of people for us to even know whether we can help them. DNS is one of those things that's going to be labor intensive to get documented well... especially from network newbs. On top of all that, many DNS servers are not in the direct control of the person with the problem; that means we can't help much besides telling them to talk to a network admin, or to call the company which operates the DNS server. In short, it's a lot of work with very little real value beyond what Super User already provides.
As for consumer devices, this site's name is irresistible to anyone with a home network problem. NESE might as well have a neon sign blinking "Dump your home networking question here!" What site is better to solve billions of peoples home networking problems than one full of network engineers? When we point out those home networking questions are off-topic, it's not uncommon for the question to chameleon into a "I just want to learn about this subject" (which seems to be a topic you'd permit). If we embrace consumer devices, our workload will significantly increase for no good reason that I can find.
Finally, I'd point out that the number of our active close voters is way lower than 100... right now, it's more like 20 active close voters; this multiples the problems described above (because the ratio calculations were based on 100 close voters).
- Note 1: I have no idea what the real number of network engineers is, but this seems like a reasonable estimate and it makes the math work well.