Last year's bowl between Texas A&M and Northwestern had a 2.69 rating, good for the 15th-most-watched game:
The teams playing obviously have an effect, as does what it's up against. Last year's game was on a Saturday morning, this year's game is on a Friday night. A better comparison for TV sake would be last year's Insight Bowl, played on Friday night with no other games at the same time. But for sure this year's game has less cache from a name-brand standpoint than Oklahoma-Iowa.
Following up on this, here are the ratings for some of the games played already (sources:
http://tvbythenumbers.zap2it.com):
Game: Teams: Viewership (in millions)/Rating 18-49
Rose: Stanford-Wisconsin: 17.02/10.9
Orange: Florida State-Northern Illinois: 10.56/7.1
Capital One: Georgia-Nebraska: 10.95/6.6
Sugar: Louisville-Florida: NA/6.4
Outback: South Carolina-Michigan: 7.58/4.9
Gator: Northwestern-Mississippi State: 2.20/1.6
Meineke Car Care: Texas Tech-Minnesota: 4.56/1.3
Russell Athletic: Virginia Tech-Rutgers: 3.94/1.1
Belk: Cincinnati-Duke: 3.89/0.9
Holiday: Baylor-UCLA: 2.92/0.9
Hawaii: SMU-Fresno State: 2.44/0.7
Little Caesars: Central Michigan-Western Kentucky: 2.66/0.6
San Diego County Credit Union: BYU-San Diego State: 2.20/0.6
Beef O'Brady's: UCF-Ball State: 1.91/0.5
Military: San Jose State-Bowling Green: 1.91/0.5
Independence: Ohio-Louisiana Monroe: 1.74/0.4