Yes. I could see a simple "Statements" vs. "External identifiers"
distinction being useful that's also reflected in the data model so
it's easier to treat these property groups in a distinct manner.
I support grouping statements about external identifiers together and distinguishing them from other statements, but I would voice caution about presenting that distinction as "Statements vs. External identifiers".
I agree with Denny that qualifiers and references should be retained for external identifiers. I would further suggest that external identifiers remain structured as properties that can (along with their values in claims) be created, updated and deleted by the community.
Given that, I think the distinction should be styled less as "Statements vs. External identifiers" and more as "External identifiers as a kind of statement". UI editing controls and data modeling as statements would remain, but "External identifiers" (e.g. VIAF identifier 113230702) would be moved to the bottom or side of statements of subject knowledge (e.g. cause of death heart attack).
Grouping together and separating external identifiers from other kinds of statements in the UI, and reflecting that in the data model and API, sounds like a great idea.
https://www.wikidata.org/wiki/Q42 is a rat's nest of meaningless (but technically useful) statements about external identifiers and meaningful statements about the subject. It's important to fix that, and I imagine we could do so while retaining all the current UI controls and data model attributes of statements in statements about external identifiers.
Best,