I think there needs to be some clarification here on what current identification-request questions are and their scope.
Let's look at the wiki:
For questions which ask about the identification of an anime/manga/character using a description; specific elements (like a character or song); or screenshots
This is currently how they are supposed to be used.
It also doesn't make much sense to keep the existing identification-request tag if we would want to split them up - as it will be confusing to users. If there is a consensus to get music-identification and et cetera, we should also get series-identification, x-identification, ...
I don't think this is the actual solution to our problem. From the original meta question:
I see why people are tagging these questions with identification-request - the asker wants something "identified", right? But this is a dangerous line of thinking. Should we tag Is Nadia voluntarily inspired by Castle in the Sky? with identification-request because the asker wants to "identify" the connection between Nadia and Castle in the Sky? What about The Kamisama Hajimemashita anime covers the manga up to what chapter? - doesn't the asker want to "identify" the chapter at which the anime ends? No, of course we shouldn't.
This problem still remains if we change this but it shifts from one tag to multiple - should we create a series-connection-identification tag? a chapter-identification tag, does chapter ids fit in manga ids? ....
Instead I propose that there should be some clarification for when the id-request tag should be used. Whether that turns out to be for questions where the series is unknown,specific media elements, or some other decision.
For my actual opinion on splitting the tag up - I'm indifferent, but I don't want to do it for the wrong reasons