Well, the depth of the 5G timeline would allow those "next gen" books to be part of canon. It'd be a different way of approaching continuity but I think it *could* work. Of course, books featuring different people in classic roles isn't likely to be a huge seller either way; the market doesn't want that. But a small imprint of "next gen" books has a chance of getting a modest-yet-respectable consumer base, while replacements across the line won't generate enough revenue to be worthwhile.
As for the larger problems with representation and new characters.....no, this wouldn't solve that problem. I don't think there's any real way to solve that problem in the direct market. There's not enough wiggle room and the audience is too entrenched in their buying habits. It'd take some pretty fantastic business and creative acrobatics to get over those hurdles, and I honestly don't think it's worth the effort when there's other markets out there that are not only accepting of this sort of thing, but hungry for it.