Having just graduated from university where 90 percent of my peers across all three years had either a MBP or a rMBP I would disagree with your statement about the students. Not one of them had an air.
Having said that I am fairy happy with the design, it might need a little refinement but I'm against them making it ridiculously thin and light at the expense of performance and features.That is why we have MBA and the new MB.The design will always be a little bulkier because it is supposed to be a PRO platform (with a combo of pro power/performance that has greater battery, space, ports and cooling requirements) and not a casual platform. A pro platform without extra ports wouldn't make much sense for me considering I am now a professional user.
There isn't a need to gut the rMBP for the sake of it and I really don't feel there will be any major changes other than the adoption of the new style keyboard so I personally think it is not too much of a risk in buying now, if people are concerned with weight and too many ports then they really would be silly to contemplate the MBP.
Just to piggyback on the point about which Macs college students are using. I judged at the US Universities Debate Championships two weeks ago, and the only people I saw using MBAs were a few of the coaches. Everyone else was using either a MBP or rMBP. It was also about 75% Mac usage overall. Since there were schools from almost every state, plus a few Canadian teams and even one from Zimbabwe, it's safe to say that the sample size was probably reflective of the wider trend on college campuses as well.