On Seven Island is an old woman who confides in you that, although most people think they're called the Sevii islands because there are seven of them, the truth is that they're called that because they were made in seven days.
I can absolutely believe that that's true, in the real world, in Game Freak's offices.
There's just too much about the Islands that reeks of rushing. What kind of name is "Lostelle" for a lost girl? The departure from numbering routes would have been a nice touch if they'd come up with better names than "Green Path" and "Water Path". In fact, the islands themselves have lousy names; the original names, which would have been at least somewhat cooler, are relegated to just a mention on the signpost. Places like Pattern Bush and Altering Cave are a letdown because the former seems all mysterious but doesn't actually have any special meaning, and the latter lost its special meaning because most places outside of Japan didn't have access to the thingy you needed to unlock it. And speaking of thingies needed to unlock something, the Sevii Islands also include Navel Rock and Birth Island, which are just another part of Nintendo not understanding that most places in the world don't work the same way as Japan.