Minecraft as a whole is consisted of a young player base in general. You cannot expect this site to be inhabited by mostly older people, while taking away/limiting younger player base's ability to create seems unfair and will certainly cause an uproar.
As for this site's design, sure, its a little outdated. But it is kind of expected since this site is pretty old, and remodeling an entire site with this kind of functionality is a hard project (if you ever coded a website then you'll probably know). Then again this site isn't owned by a company that can make big decisive moves, neither have big budget to begin with.
Any kind of big forum websites honestly is some kind of their own mess. When you have a site this large, it is hard to police and regulate where goes into where, and it will always seem like a bunch of stuff clumped together.