Weirdly enough GW is right on schedule. They essentially release a new 40k edition every 4 years, almost like clockwork. Or at least since 2nd edition.
Boarding patrol seems to have been kicked around for a bit. There was a white dwarf version, then Kill Team version was pretty popular, and now they've upgraded it to the full table top.
Its an interesting idea really, although it feels like the equivalent to something like Blood in the Badlands, where it was a standalone campaign book,