Thomas Dalton schrieb:
1.) It establishes the fact that fiction articles are only notable if there is out-of-universe infomration available
Information is neither "in-universe" or "out-of-universe", it's just a collection of facts. It's the presentation of that information which is in- or out-of-universe, any in-universe content can be re-written out-of-universe (although a large amount of in-universe content is often a clue that the article needs trimming, so I'm not suggesting blindly rewriting articles). I think what you're trying to say is that there should be non-primary reliable sources in order for something to be notable, which is probably a good rule of thumb.
IMHO it's not only about notability, but also about a general sanity-check. Articles featuring thousands of details of some fiction franchise without any information as to its real world framework must be discouraged. Going over notability is just one of several ways to address this issue - and a good one, imo, simply because fiction articles are not exempt from the burden to establish notability of the subject.
Also, I don't think any in-universe content can easily be rewritten as out-of-universe, you'd need incredibly detailed sources for that, if I interpret policy correctly. A section describing the character traits of some alien race would need to be rewritten along the lines of why and how the authors/designers/directors made the character that way. In most cases, sources like that don't exist - which shouldn't keep us from implementing the proposed guideline changes. The basic premise is that in fact there is a lot of unsuitable material, we just need plausible syntax to get rid of it while preserving as much useful material as possible.