The island is fairly high up on Vanda Nosseo's priority list, once they notice the planet exists. (This takes some doing, since practically the entire thing, including all the people on it, is magical, but with forensic conjuration they eventually manage it.) It's recently politically unified, produces a sizable fraction of this world's written works (almost all in one language, many of them about the complex internal details of their magic system, and a surprising number from authors who have been irregularly writing every few centuries), and seems to have a level of urbanization that usually requires the steam engine and a century or two to learn how to use it. The natives look like they might be a human ethnicity that doesn't exist on any known planet or also might be from an uncontacted Warp species with suspiciously near-human ancestry, but either way they don't seem far off the human norm.
Oh, and they're nonreductionist, which might accelerate the timetable just a little bit.