Op let me start by stating the fact that your idea is a little vague. Now we already have a beginner and help board and there should not be any child board. Infact if there were what would you name it? Help for newbies? Never forget the fact that not only newbies need help as many a time I have come across high ranked members of the likes of Pmalek NotATether , BlackHatCoiner, Phillipma1957 and many more ask for some help with some Bitcoin technicality related problems they have a hard time solving.
What you should understand Op is the fact that repeated topics by newbies especially introduction by newbies won't be stopped any time soon it's infact normal already. The best that could happen is that moderators would simply nuke posts that have very low quality and are useless.
A newbie who really wants to learn on the forum will simply find his way to the forum search button.
“Beginners and help" two words different meaning. I consider this board as a place where all forum members visit to learn new ideas and information that both benefits newbies as well as old members. Browsing this forum, contents here don't only focus on learning bitcoin terms, it also teaches users about newly imposed ideas on bitcoin and how it'll help forum members. New fraudulent activities relating to bitcoin also get shared here to help save forum members from getting scammed.
A lot of informational help can be seen here. It validates your idea of old members coming to seek help in this same board. Besides, I think Op is asking for a childboard that focuses on newbies alone. Because some of the contents shared here are too vague for beginners to learn. The type of help you see old members seek here may not be easy for us beginners to comprehend the jargons and terms used in the thread. This shouldn't be a problem, beginners can scan through the pages for threads that solves their problem. But, Op only is bothered about the long pages one would go through before getting the right answer. I always get surprised how users easily share links to threads patterning to the question a user asks in the forum.