Numbers is all about a journey. The Israelites have been trying to get to the Promised Land for the last forty years. Now here they are, literally looking down on this land flowing with milk and honey, when the book ends with this:
These are the commandments and the ordinances that the Lord commanded through Moses to the Israelites in the plains of Moab by the Jordan at Jericho. (36:13)
Yup. You read that right. The group is standing on the plains of Moab. Right about to cross the Jordan River. Right next to Jericho. After all that build up, Numbers ends and not one single person has set foot in the Promised Land.
It's actually quite the cliffhanger. Here we are on the steps leading up to Mordor and suddenly the hobbits decide to sit down and rest. But because the battle to claim the Promised Land is so epic itself, it really does deserve its own book. Deuteronomy? Nope. You're gonna have to wait until we get to The Book of Joshua to see Israel kick some butt and take some names in Canaan.