If student loans could be discharged in bankruptcy as they absolutely should be then lenders would be much more careful about giving them out. Strong students at good schools would still be able to get loans. Week students at fly by night for profit diploma mills not so much. Some students would have to work a little to finish school. Schools would not be able to ramp up tuition as much as they wanted without losing enrollment. College in general would be much much cheaper then it is today. Lets look at what happened to the cost of college after this change.
Why would a good student at a good college pose a lower credit risk if student loans could be discharged in bankruptcy? I would say it would be the opposite, as the better informed student would be more likely to declare bankruptcy, as they know the consequences and affects of bankruptcy, and a good student is more likely going to be well informed.
You previously mentioned that bankruptcy will take away a debitor's assets, however students do not have any assets and do not use student loans to purchase additional assets; student loans are used to pay for an education and for living expenses while a student is in school.
If student debt could be discharged in bankruptcy then
any rational student would declare bankruptcy as soon as they are sure they are finished with school (they do not want to get any additional advanced degrees). Since the student would have no assets, and would have a lot of debt, the student would lose nothing because there would be nothing to lose, but would gain the fact that s/he no longer needs to repay the amount s/he promised to pay their lender