If someone says that it was not planned to continue the arc - I'll bite them. It definitely was. I mean, did it not come out around the time that Blood War anime started? I am sure Tite is working on it, probably just holding it back till the anime ends. Heck, this one-shot may become the proper prologue and announcement of the proper continuation at the same time. Not publishing the manga right away give more leeway, when anime adaptation of the new arc starts along side the manga itself, since it will already be ahead.
Speaking of the one-shot itself... There is not much to say really, because we weren't show that much. These are all hints, nothing more. It definitely looks like a beginning of a movie or a filler series, though. I mean, it's really abrupt with no preparation beforehand. Which maybe it is. Maybe it's not introduction to a whole big arc, but rather, introduction to an introduction. I mean, they would need a way to get to Hell, right, and if I remember correctly, Hell Verse movie is not considered canon, so whatever they did there (and I don't remember what they did), it probably won't work in real Bleach universe. It probably will introduce more layers of reality or multiverse, and maybe help explain how the witches actually fit Bleach world without having similar rules even.
