Huh, I was under expecting at least several more years worth of Vanguard stories. But if this is the end, I'm sure it'll be a good one. The authors haven't let us down yet, and I don't see any reason to expect them to in the future.
Although it does say the end of the epic saga begins, it doesn't say anything about how long the end will be. For all we know this "end" could take another 5 or 6 books.