From Vettel's results with the tight coke bottle in China (considering he is no slouch), there needs to be an additional aspect to gain back downforce and speed.
What is peculiar is that Lotus, who has a similarly tight coke bottle, has been doing well without the same coanda exhausts used in Sauber and Maclaren. Grosjean and Raikkonen have been doing very well in qualifying:
Australia:
P3 Grosjean
P5 Webber
P6 Vettel
P18 Raikkonen
Malaysia:
P4 Webber
P5 Raikkonen
P6 Vettel
P7 Grosjean
China:
P4 Raikkonen
P6 Webber
P10 Grosjean
P11 Vettel
Lotus E20 Rear (From Bahrain, but similar to China)
(Photo from Crucial Extreme):
Vettel's China '12 RB8 Rear:
I would like to know more about the benefits that the RB5-7 sidepods gave compared to, say, the Maclarens or the Toro Rosso's double floor. But, it appears that the coke bottle area isn't as keenly a design area to be strict upon in the RB as before. I expect some radical deviation from the RB5 through 7 after the testing and the season goes on the European leg.