The Graduate tax might not be a bad thing as long as it is progressive enough.
It would remove the need for upfront payment of fees, removing the necessity for hefty loans - although I suspect a lot of people would still need some assistance for buying books etc. But in the actual studying period, students would potentially accumulate less immediate debt. If the subsequent tax when they graduate and find work is progressive, and those who find vast riches pay appropriate thanks to the University system that made them, it could actually be a better system than the one we have now.
They should make repayments automatic (I'm sure they will). My £18 a month to the SLC goes out of my account by PAYE and I barely even notice.
If the new system encourages careful thought before people dive on into a course, that might also be a plus.
Depending on how exactly they implement this it could be better, it could be a lot worse. I think in the long run, successful students will pay more than they do under the current system, but if the implementation is relatively painless, I'm not sure I'm against that. I am choosing to remain hopeful that it represents a positive development.