Technically, etymology is only about the origin of certain words, while origin comprises also the history of, e.g., grammatical features. However, for the latter we usually use history, though its tag-wiki excerpt is more restrictive, limiting it only to the history of words.
I thus propose to resolve this situation by:
Synonymising origin to etymology.
In meinen Augen ist die Unterscheidung zwischen rechtschreibung und orthographie künstlich und in der Praxis wenig relevant. Bei der Schreibung bestimmter Wörter werden mit Sicherheit die dahinterliegenden Regeln erwähnt werden, während Antworten, in denen es um die Regeln geht, sicherlich mit Beispielen ausgefüllt werden. Ich schlage deshalb vor, beide Tags ...
Da heute immer seltener Griechisch und Latein gelernt werden halte ich den Begriff "Rechtschreibung" für besser geeignet, als Orthographie, das neue Tag zu werden, weil er für kaum jmd. eine Barriere darstellt.
Indeed there has been a lot of discussion on the language tags should be in. The decision to have them in English was made at a very early stage of this site's existence, then there were clearly outlined reasons why we chose English over German.
Tags by now are well established and users who subscribe to any of them are used to them. It may not be a good ...
No, we don't need it at all. Any kind of question should address a particular issue and the tag should indicate the kind of issue. But being non-native is not a helpful information here (Not to mention, that we're able to tell whether someone is native German or not, anyways).
Agreed that having only one tag to cover questions on numbers or numerals should exist.
The tag numerals is now merged to numbers with numerals being a synonym to numbers in analogy to English Stackexchange.
Good you brought that up. Both tags are already synonymized to grammatical-case being the "master" tag of its synonym cases.
This also is why you had the choice for grammatical-case whenever you tag a question with cases.
I merged these tags now so that cases will be replaced by grammatical-case from all questions.