This would make switching between your fonts and other fonts more trouble than it’s worth. Nobody reads the readme.txt file, so users wouldn’t know what’s going on. Especially not the users who didn’t buy or spec the fonts in a document they open years after it was created.
And it only takes seconds to change /guillemetright /space to /guillemetright /thinspace with find and replace. So you wouldn’t be doing the user a big favor.
I think it’s premature to say “̌Color will be the new Italic. Color will be the new Bold.” when there is currently no indication that end users will ever have worthwhile color font support outside of web browsers.
And I think it’s absurd to think that color will become common for presenting text. That’s as arrogant as designers in the 2000s who thought all text would be presented as expressive postmodern layouts like those found in the books of Howard Stern and Mark Danielewski. Readers read because they’re interested in the content written by the author, not because they’re interested in masturbatory layout novelty. Color might become common in headlines again (where it has come and gone plenty in the past) but it’s not going to become much more common in text than it is now.