It's just a tag I thought looked good for use with the COMPOSE feature of a skippable FILE! or TAG! that shows you which slots to compose. I think that's pretty great. If you want you can pick another tag.
(The predicate functionality is currently disabled, pending more research on how predicates will be done system-wise...)
There's definitely a lot to think through regarding this. I'll be the first to say that.
But I feel like /foo/bar being legal is feeling fairly close to non-negotiable for me. And if /foo/bar is legal, I don't want that to be a PATH! and /foo to be a REFINEMENT!.
I wish there was more experience with this. :-/
This might be something you find you appreciate more with time. Hopefully you can be happy enough by virtue of getting back #issue as a string type, and there is %file ... that's pretty good coverage.
It was historically the case that quoted values returned a distinct type, so this isn't a new behavior.
rebol2>> (type? first [x])
== word! ; new plan would be @[word]
rebol2>> (type? first ['x])
== lit-word! ; new plan would be @['word]
I would counter that I am skeptical of the use cases for such an indiscriminate "I don't care if it's quoted or not" test. I've previously pointed out that if the default is for dialects to treat quoted items the same as non, there is no incentive for users to be clean about stripping quotes off...and things will become a mess, making it hard to reclaim quoting for real purposes later.
I just don't see it coming up that you want to ignore how many quote levels there are and treating everything the same regardless. The cases where this would make sense seem covered by NOQUOTE.