As Cougarpride mentioned above, when we scheduled Mizzou, part of the deal was that Mizzou would provide us with the replacement game.
Because your memory is obviously a bit fuzzy, we had UNLV and Idaho state on next year's schedule before we signed with Mizzou. The Mizzou game was the same week as the UNLV game. Part of the deal with getting the Mizzou game was giving UNLV our Idaho State game. Idaho state already had a full schedule, so we couldn't move the ISU game to another open week. The result of scheduling Mizzou was that we needed a 12th game to replace ISU. Mizzou agreed to go out and find us the game. What they came up with was Wagner.
Wagner is probably marginally better than ISU. Mizzou is a huge upgrade over UNLV. Wagner/Mizzou is a package deal that replaced ISU/UNLV.