An upside to fees may be that students value education more and may take it more seriously. Plus many universities will have to raise their game in order to attract students and show how they offer value for money.

I was an overseas student, thus paid fees, when university was 'free' to UK students. Warning: I am going to make a generalisation, but I felt at the time that many overseas students could be found in the library - making sure that they got a good return on investment, and many UK students (and a few overseas scholarship students!) took things a little less seriously.