I don't mind the changes apart for the approval criteria. If you do want to stick with having 2 diffs no matter what when you have an Expert or above diff, then I suggest loosening the lower limit (that is, Insane) to Hard or Normal though I'm reluctant with the latter considering I don't think players at that skill level have enough physical and/or mental stamina to keep up with a five minutes long song.
Now here's another thing I wish to adress :
Now here's another thing I wish to adress :