* This tool should be clear that it's geared towards 17 year olds that are mature enough to be able to view college as a financial investment. That's not to say that college can't be chosen for the experience of it as well, but I don't think you can recommend colleges on such a personal variable. This type of site can be a great tool if you're willing to put that aside for a moment and merely get information about potential return on an investment, which is useful for everyone regardless of how they feel about what college ought to be.
* Factor in how confident a student is in what they want to study. I think the largest cost sink is in people who don't know what they want to study, but decide to go to an expensive school and say that they'll figure it out in their first two years. What happens when you don't, or school ends up being hard, and you have friends made and leases signed and now you've locked yourself into paying $80k for something you're not going to see return on? Would you have made that decision before?
* Average salary after school is an awful metric. You can't group engineers with those that study humanities and then present that as a meaningful statistic. It makes the person studying philosophy feel more confident in spending money, and it makes the person studying engineering more likely to deviate from liberal arts schools, when in actuality a school can accommodate both groups well but with somewhat different outcomes.
* How do you run a site like this and not ask what their SAT / ACT scores are? This is most certainly the most predictive factor for where you'll go.
* How do you not ask where they live, and talk about in-state tuition rates?
Ultimately it's a nice idea with poor execution, but it's close.