re: Are college football rivalries still important?

The problem you are having is you are taking a lot of the emotion out of it which is why you think rivalries aren't a big deal. The great part about rivalries is that it doesn't have to have a lot on the line in the scheme of national championship or even your conference. It is an enemy that you have history against (for good or bad) and because of that tradition of playing each other you want beat that person even more so than the random other school.

Every sport and almost all aspects of our lives gravitate towards rivalries:

Yankee's/Red Sox
Falcons/Saints
High schools
Your teammates
Your siblings
Republican's/Democrats
That uppity a-hole in the office
etc.

They are a part of the human psyche and yes the sport would be much much worse if you forced college teams to play random other schools every year. The only hope you would have is to be able to meet your rival in the playoff so you could beat them to a NC.