Ketch, I think the OU game will still have immense importance. Winning that game will be a spring board for the rest of the season. Losing it puts you behind the 8ball.
I somewhat feel this game is going back to what it was before the BCS era...pre-2000.
Historically, OU is/was a big-time program that was always on our schedule.
Winning it puts us squarly in the Top 5 in rankings early in the season (certainly Top 10). We're able to hold that spot, it gives us a favorable position in the Play Offs. (assuming we're undefeated after the game, obviously).
Historically, the winner was in the driver's seat for the conference and big-time Bowl consideration and possible Natty consideration.
The situation is no different than what life was like "back in the day". That is part of the glory of that game: The contest is settled early in the season, as it always has been.
I think it is still the spring board it always has been. Win and we're in the driver's seat. Lose and we're behind the 8-ball.
(This is assuming OU gets things turned around, which I think they will)
edit: Will it have less importance? Possibly, but not by much.