Based on the future trends I believe it is doing ISU and Iowa a disfavor to play every year. ISU (also WV) is island of the Big 12. The majority of the teams they play are from Texas and Oklahoma (6 of 9 games). ISU really needs to look at re-establishing series with some old Big 12 members, Missouri and Colorado come to mind. They would get more regional or national exposure than playing Iowa. Eight of ISU's games involve on three states; Texas, Oklahoma, and Kansas. This year Iowa's conference opponents are from 6 states stretching from Maryland to Nebraska.
I agree with the beginning, I think we are to the point where Iowa State and Iowa are actually hurting themselves by playing each other. I think if Iowa State fans were honest with themselves they would have been a little concerned about selling tickets without Nebraska and Iowa on the schedule. We are there and at least for the time being it doesn't appear to be an issue.
However my conclusion is completely different. The last thing Iowa State should do is sched more power conference schools. They should sched a 1-aa and the two worst bcs teams they can find. Iowa State needs wins to sustain fan support. It gets a boost when beating Iowa but it also is diminished when losing to Iowa.