The tint is to help your eyes in low light. I really enjoy it at night. On my n5 I had to use a screen filter; this works much better so I'm happy.
I also wonder if yours had an abnormally strong tint. I don't notice it unless its almost all the way down.
I don't notice the tint unless I am both on the lowest brightness AND adaptive brightness is on.
At lowest brightness with it off, there is no tint.