Well, I'm not sure about that. Certainly they've not
revealed a link to Xenoblade, but that's not the same thing.
Way back when it was first revealed, right at the end of the trailer, there was a brief glimpse of a character who looked a lot like Shulk, which might suggest that there
is, in fact, a link. Or, of course, that's something that might have been quietly removed since then, since I don't think they ever elaborated on that character.
I wouldn't
assume there's no link. There may yet be no link, it's true, but I wouldn't assume it.