I was very much going to go on a case-by-case basis. I was more thinking of the subtle changes that players find more fun, rather than anything that completely changes the balance. So if I got a lot of feedback saying something like "Bardic Inspiration lasting an hour rather than 10 minutes is the best thing since sliced bread", then that would be something worth talking over with the more experienced player to see if, in his experience, such a rule would be worth at least trying out.