That might work for Computer Science where grads can be employed quickly and at very solid wages but it won't meaningfully apply for most fields like business, chemistry or physics.
which will result in more people going into degrees where people can be employed quickly at solid wages, which is good
which will result in a scarcity of people going into the fields you mentioned, which will increase the wages in those fields which will incentivize people to go into them
this, like most things, is a supply and demand problem, and we have created too much supply in certain areas
I want a populace educated in those fields, and there are much betters way to do it than robbing the citizenry. One way might be to agree to work for a company afterwards who might pay for it, another to join the army in exchange for paying for it. Another might be to stop ensuring loans so that prices fall and become attainable to someone working part-time and going to school. Loans become not such a burden then, if you even want them. Lots of ways.
"Tie student loan funding to the value of a degree" is a fantasy. In the real world, what would actually happen is that student loans would become limited to those who could put up some sort of collateral, which for the figures involved involved in a typical college education would largely limit it to the already-wealthy.
Giving out blank check loans with no underwriting standards does not help the non wealthy. It results in what has already happened in the US, schools collect as much tuition money as they can since why not, and the non wealthy end up indebted for the rest of their life.
The only real way to help is by giving out money that they don't have to pay back.